西北植物学报 Acta Botanica Boreali-Occidentalia Sinica

Volume 44,2024 Issue 9

Publication date ：2024-09-05

Effects of exogenous calcium on growth and photosynthetic characteristics of Marigold under salt-alkali stress

WANG Jing, JIANG Qian, TIAO Tiantian, WANG Luoxuan, WANG Yan, XIAN Xulin

2024,44(9):1345-1354 DOI: 10.7606/j.issn.1000-4025.20240185

[Abstract] (43) [HTML] (0) [PDF 4.14 M] (2004)

Abstract:
【Objective】 To explore the effects of exogenous CaCl2 on the growth and photosynthetic characteristics of marigold under saline-alkali stress, and to provide theoretical support for the application of CaCl2 to improve the cultivation efficiency and product quality of marigold on saline-alkali land.【Methods】 Taking Tagetes erecta L.seedlings as test materials, pot experiment was carried out to observe the growth phenotype, photosynthetic pigment content, photosynthetic gas exchange parameters and chlorophyll fluorescence parameters of Tagetes erecta L.seedlings by watering (CK1), root irrigation with 80 mmol / L mixed saline-alkali solution ( NaCl∶NaHCO3 = 1∶1, CK2 ) and root irrigation with saline-alkali followed by foliar spraying with four concentrations of CaCl2 solution [ 5,10,15,20 mmol/L ].【Results】With the prolongation of saline-alkali stress time, the plant height, stem diameter, root configuration and root-shoot ratio of marigold plants showed a gradual upward trend, and the net photosynthetic rate ( Pn ), transpiration coefficient ( Tr ), stomatal conductance ( Gs ), chlorophyll a content ( Chl a ), chlorophyll b content ( Chl b ), total chlorophyll content ( Chl t ), initial fluorescence ( F0 ), maximum fluorescence ( Fm ) and maximum photochemical efficiency ( Fv/Fm ) of leaves showed a downward trend, while intercellular CO2 concentration ( Ci ) showed an upward trend. After spraying different concentrations of CaCl2 on the leaves, the change range of each index decreased. There was a concentration effect, and the effect of 10 mmol / L CaCl2 treatment was the best. On the 20 th day of stress, the Chl a, Chl b, Chl t, Pn, Tr, Gs, F0, Fm and Fv / Fm of leaves treated with 10 mmol / L CaCl2 were significantly higher than those of CK2 by 52.39 %, 48.51 %, 46.78 %, 45.53 %, 49.51 %, 49.57 %, 31.60 %, 43.80 % and 32.83 %, respectively. The root-shoot ratio and Ci were significantly reduced by 22.60 % and 30.91 %, respectively.【Conclusion】 Spraying 10 mmol/L CaCl2 on the leaves could significantly reduce the decrease of chlorophyll synthesis precursors in marigold leaves under saline-alkali stress, increase the electron transport rate of PSII, enhance the photosynthetic capacity of leaves, and effectively improve the growth of plants.

The Effect of Shade Netting on the Quality of Marselan Grapes and Wines

LI Lei, GU Weijie, SU Wangchun, CHEN Keqin, ZHANG Kekun, FANG Yulin

2024,44(9):1355-1364 DOI: 10.7606/j.issn.1000-4025.20240266

[Abstract] (20) [HTML] (0) [PDF 1.68 M] (2005)

Abstract:
【Objective】 There are problems of excessive sugar accumulation and serious organic acid degradation in wine grapes cultivated in hot areas. As sunshade net has wide application value in fruit cultivation in hot areas, this experiment conducted sunshade net test on the main wine grape "Matheran" in the eastern foothills of Helan Mountain in Ningxia, aiming to provide theoretical basis for solving the problem of wine grape quality disharmony in hot areas.【Method】 In this experiment, the wine grape "Matheran" was used as the material. From the color transformation period (July 29) to the harvest period (September 22), sunshade nets of different widths and colors were set up on both sides of the grapes, and then the sugar components, organic acids and phenolic substances of the grapes and wine were analyzed.【Results】(1) RE1 treatment significantly reduced the sugar content of grape fruits, and sunshade treatment significantly inhibited the degradation of organic acids in grape fruits and wine; (2) Sunshade net treatment can increase the contents of total flavonoids in grape fruits, and reduce the contents of total tannins, total anthocyanins and total flavantriols in grape fruits; (3) Sunshade net treatment reduced the contents of total anthocyanins in wine, and BL0.6 treatment increased the contents of total tannins, total phenols, total flavonoids and total flavantriols in wine.【Conclusion】 RE1 treatment has the most significant effect on reducing sugar and increasing acid and increasing phenolic substance content in grape fruit, WH1 treatment has the most significant effect on increasing organic acid content in wine, and BL0.6 treatment has the most significant effect on increasing phenolic substance content in wine.

Effects of chemical fertilizers reduction and application of microbial fertilizers on the photosynthetic physiological characteristics of Lilium davidii var. willmottiae

CHEN Xiaoli, YANG Hongyu, HAN Jia, MAN Huali, LI Yuanpeng, SHI Guiying

2024,44(9):1365-1375 DOI: 10.7606/j.issn.1000-4025.20240206

[Abstract] (17) [HTML] (0) [PDF 895.31 K] (1987)

Abstract:
[Objective] The study aims to explore the effects of chemical fertilizers reduction and application of microbial fertilizers on growth, photosynthetic physiological characteristics of Lanzhou lily（Lilium davidii var. willmottiae）, and to provide scientific fertilization management for the continuous cropping of Lanzhou lily. [Methods] From 2019 to 2021, fertilization was applied in experimental field of Lanzhou Lily which was located in alpine humid area of Gansu Province, the study set up three different treatments: 100% chemical fertilizers, chemical fertilizers reduction by 30% with microbial fertilizers, chemical fertilizers reduction by 50% with microbial fertilizers. After three years of continuous fertilization, the changes of physiological indexes such as growth, photosynthetic characteristics and antioxidant enzyme activity of each treatment were investigated. [Results]Compared with 100% chemical fertilizers, chemical fertilizers reduction by 30% and 50% with microbial fertilizers could improve the strong seedling index, photosynthetic characteristics and antioxidant enzyme activities of Lanzhou lily to different degrees, the treatment of fertilizers reduction by 30% with microbial fertilizers had best effects between different treatments. Under the treatment of fertilizers reduction by 30% with microbial fertilizers, plant height, stem thickness, leaf area, underground biomass and strong seedling index increased significantly, the photosynthetic pigment content increased, maximum photochemical efficiency of PS Ⅱ（Fv/Fm）、actual photochemical quantum efficiency(ΦPSⅡ)、electron transfer rate(ETR) increased, None photochemical quenching coefficient（NPQ）decreased, the enzyme activity of the antioxidant (SOD、POD、CAT、APX) increased significantly , the content of osmoregulatory substances（proline、soluble protein）increased significantly, the content of malondialdehyde decreased, and the root vitality enhanced significantly. [Conclusion] The fertilizers reduction by 30% with microbial fertilizers could promote the growth of Lanzhou lily, enhance leaf photosynthesis, improve protection enzyme activities and osmoregulatory substances, alleviate the degree of membrane lipid peroxide, and improve root vitality. This study could effectively improve the cultivation environment of continuous cropping Lanzhou lily.

Effect of Melatonin on Growth and Biochemical Properties of Grapevine Suspension Cells under Low Temperature Stress

WANG Tiaoye, LIANG Jing, LIU Yashi, WANG Xin, MAO Juan, CHU Mingyu

2024,44(9):1376-1385 DOI: 10.7606/j.issn.1000-4025.20240094

[Abstract] (16) [HTML] (0) [PDF 2.87 M] (1981)

Abstract:
【Objective】To analyze the effects of melatonin (MT) on the growth, biochemical characteristics and expression of cold-responsive related genes in Grapevine suspension cells under low-temperature stress, to screen for the appropriate MT concentration, and to investigate the mechanism of action of MT in enhancing the cold tolerance of Grapevine.【Methods】Using ''Pinot noir'' Grapevine suspension cells as test material, we investigated the effects of different concentrations of MT [0 (CK), 50 (T1), 100 (T2), 200 (T3), 300 μmol/L (T4)] on the growth of the suspension cells, the content of malondialdehyde (MDA), the content of proline (Pro) and the expression of genes related to cold-responsive genes, at a low-temperature (4 ℃) stress, Proline (Pro) content, antioxidant enzyme activities, and the trends of gene expression changes related to cold response to T2 treatment. 【Results】(1) Under low-temperature stress, the dry mass of cells in each MT treatment showed a trend of increasing then decreasing and finally stabilizing or decreasing during the culture cycle, and was significantly higher than that of CK at the end of the treatment period.(2) The MDA and Pro contents of each treatment firstly increased and then decreased with the time of treatment, and reached the peak at 24 h or 48 h. The MDA contents of each MT treatment were significantly lower than that of CK, and the Pro content was significantly higher than that of CK, and all of them were significantly higher than that of CK, and were in the same order. The MDA content of each MT treatment was significantly lower than that of CK, while the Pro content was significantly higher than that of CK, with T2 treatment being the lowest or the highest; (3) the antioxidant enzyme activities of each MT treatment were significantly higher than that of CK during the same period, with T2 treatment being the highest; with the prolongation of time, the activities of POD and CAT of each treatment firstly rose and then fell, while the activities of SOD and APX firstly fell and then rose, and reached the highest at 24 or 6 h, respectively. (4) The relative expression of cold-responsive genes VvCBFs, VvICE1, VvRD29B and VvKIN-2 in T2-treated suspension cells were all up-regulated significantly at different times compared with the corresponding CK.【Conclusion】Under low-temperature stress, the appropriate concentration (100 μmol/L) of MT could increase the relative expression of antioxidant enzymes and cold-response-related genes, increase the Pro content, decrease the MDA content, and ultimately enhance the low-temperature tolerance of Grapevine suspension cells.

Growth and physiological characteristics of Arnebia guttata at different altitudes in Wushi County, Xinjiang

NING Peng, YUAN Zhiguo, QIAO Qiufen, WANG Ling

2024,44(9):1386-1394 DOI: 10.7606/j.issn.1000-4025.20240124

[Abstract] (20) [HTML] (0) [PDF 982.97 K] (1989)

Abstract:
Abstract: [Objective] The study aims to investigate the growth and physiological characteristics of Arnebia guttata at different altitudinal gradients, in order to understand its ecological adaptation mechanisms under different habitat conditions and provide a theoretical basis for the conservation and utilization of the wild resources of Arnebia guttata. [Methods] Arnebia guttata in Wushi County, northwestern Tarim Basin, was chosen as the research subject. The leaf morphology, growth indicators, photosynthetic pigments, proline, soluble osmoregulatory substances malondialdehyde content, and the activities of antioxidant enzyme were measured at five different altitudinal sites (i.e., 1155, 1227, 1332, 1533, and 2137m). [Results] (1) The plant height, aboveground biomass, total biomass, leaf area , specific leaf area, and the contents of chlorophyll a and chlorophyll b of Arnebia guttata were highest at the lowest altitude of 1155 m and decreased with increasing altitude, reaching the lowest at 2137 m. Among them, plant height, aboveground biomass, and leaf area were decreased significantly (P<0.05) by 22.89%, 31.77%, and 26.58%, respectively. (2) The minimum values of specific leaf weight, root/shoot ratio, and carotenoids content, carotenoids/chlorophyll ratio, malondialdehyde, proline, soluble sugar, and ascorbate peroxidase, peroxidase enzyme activity of Arnebia guttata all appeared at 1155 m, and increased significantly with increasing altitude, reaching the maximum value at 2137 m (P<0.05). [Conclusion] The environmental conditions of lower altitude in the area are more conducive to the growth and biomass accumulation of Arnebia guttata, making it the most suitable growth area for Arnebia guttata. As altitude increases, the physiological stress on Arnebia guttata intensifies, the degree of lipid peroxidation increases, and its growth is inhibited. Arnebia guttata also adapts to the increasingly harsh natural environment at high altitudes by adjusting its life strategy, increasing the content of soluble osmotic regulatory substances, and the activity of antioxidant enzymes.

Effects of fertilization on resource allocation of two exotic plants of Salvia

ZHANG Yanting, FANG Xiao, GUO Rong, ZENG Shengqi, YAN Xiaohui, HU Shijun

2024,44(9):1395-1401 DOI: 10.7606/j.issn.1000-4025.20230763

[Abstract] (23) [HTML] (0) [PDF 569.25 K] (1981)

Abstract:
[Objective]To understand the invasion mechanism of the invasive plant Salvia tiliifolia. [Methods]The differences in growth, reproduction, and defensive traits between S. tiliifolia and the cultivated S. splendens were studied under different fertilization conditions. [Results]Except for root dry weight and height of S. tiliifolia, biomass of both plants significantly increased under high-fertilization conditions compared to the control. The flower flavonoid and tannin contents of S. tiliifolia and the leaf tannin content of S. splendens were significantly higher under high-fertilization treatment. The soluble protein content of S. splendens and the content of three nutrient indexes of S. tiliifolia significantly increased under high-fertilization conditions. With increasing fertilization, the biomass, flower chemical defense, and nutrient content of both plants increased, while physical defense and leaf chemical defense decreased. Under the same conditions,the plant height, number of leaves, number of flowers of S. tiliifolia were higher than that of S. splendens. Additionally, S. tiliifolia had higher leaf chemical defense and physical defense than that of S. splendens, while the flower chemical defense and nutrient content were lower in S. tiliifolia compared to S. splendens. Notably, S. tiliifolia showed higher leaf chemical defense than flower chemical defense, whereas the opposite was observed in S. splendens. [Conclusions]Both plants reduce defensive investment and increase growth and reproduction under conditions of abundant resources. S. tiliifolia focuses on leaf defense, with stronger growth, reproduction, and leaf defense than S. splendens, which focuses on flower defense. The flexible resource allocation strategy of S. tiliifolia is advantageous for successful invasion.

Study on the antibacterial activity and allelopathy of the flavonoids extracts from Eleutherococcus brachypus leaves on Allium cepa

YANG Jianxia, FAN Xiaofeng

2024,44(9):1402-1410 DOI: 10.7606/j.issn.1000-4025.20240095

[Abstract] (19) [HTML] (0) [PDF 2.18 M] (1997)

Abstract:
[Objective] The study aims to explore the antibacterial activity and allelopathy of flavonoids from leaves of Eleutherococcus brachypus, and to provide the basis for the development of plant-derived antimicrobial agents and their allelopathy in plant protection and agricultural production. [Methods] Its leaves as raw materials, the flavonoids were extracted from E. brachypus leaves by ultrasonic-assisted extraction, the antibacterial ability of leaf flavonoids extract against Staphylococcus aureus, Bacillus subtilis, and Salmonella were evaluated by the antibacterial sphere, minimum antibacterial concentration (MIC), in the meantime, the allelopathic effects of leaf flavonoids extract were studied by measuring the apoptosis rate, malondialdehyde (MDA) content in apoptosis cell, and root and bulbil growth inhibition rate of onion epidermal cells under stress of different concentrations (100%, 50%, 25%) the flavonoids extracts from E. brachypus. [Results] (1) The yield of leaf flavonoids from E. brachypus was 42.3 mg/g. (2) Under the same concentration, the antibacterial activity of leaf flavonoids against the gram-positive bacteria (S. aureus and B. subtilis) was significantly higher than that of the gram-negative bacterium (P<0.05), and the antibacterial activities were proportional to the concentration of leaf flavonoids extracts of E. brachypus. The maximum antibacterial coil diameters of the leaf flavonoids extracts of E. brachypus against S. aureus, B. subtilis, and Salmonella were 24.4, 22.1, 18.3 mm, respectively, and the minimum inhibitory concentration of S. aureus, B.subtilis, and Salmonella were 1.31, 2.63, 5.25 mg/mL, respectively. Considering the antibacterial coil diameter and MIC of the three tested species, the antibacterial ability was successively decreased as: S. aureus, B. subtilis, Salmonella. (3) Different concentrations of leaf flavonoids from E. brachypus could induce apoptosis of the upper epidermal cells of Allium cepa L., and many morphological characteristics from apoptotic cells in A. cepa L. were examined under a light microscope, such as, cytoplasmic breakdown and collapse, many cytoplasmic vesicles formation, at the same time, the nuclear membrane fractured and even disappeared, chromatin condensation and edging, finally, the apoptosis rate and MDA content in epidermal cells were also increased with treatment concentration. (4) Moreover, the growth of root and bulbil of onion bulb were inhibited under different concentrations of leaf flavone extracts treatment, and the relative inhibition rate of root and bulbil growth of onion bulb was also concentration-dependent, compared to the control. In conclusion, leaf flavonoids of the E. brachypus had antibacterial activity, apoptosis-inducing of plant cells, and inhibiting the growth of roots and bulbil of A. cepa L. These findings suggest that the leaf flavonoids extract from E. brachypus had certain antibacterial activity, and it also had some allelochemicals phytotoxic effects on apoptosis-induction epidermal cell of A. cepa L., and growth inhibition of root and bulbil of onion bulb by inducing membrane lipid peroxidation.

Screening and validation of interaction targets for wheat E3 ubiquitin ligase TaRING1

WANG Jinmian, HAN Luxin, KANG Zhensheng, LIU Jie

2024,44(9):1411-1419 DOI: 10.7606/j.issn.1000-4025.20240276

[Abstract] (15) [HTML] (0) [PDF 6.99 M] (1993)

Abstract:
【Objective】 In order to explore the role of TaRING1 in the interaction between wheat and stripe rust, analyze its mechanism and provide theoretical basis for the green prevention and control of wheat stripe rust.【Methods】 The interaction target protein of TaRING1 was screened by yeast two-hybrid technique and verified by bimolecular fluorescence complementation and luciferase complementation assays. The ubiquitin function of TaRING1 was verified by ubiquitination experiments. The subcellular localization of target TaRIP92 was observed by transient expression in Nicotiana benthamiana and protoplast transformation in wheat. 【Results】 Using TaRING1 as bait, the interaction target TaRIP92 was screened by yeast two-hybrid technology, and the interaction between TaRING1 and TaRIP92 was verified by LCA and BiFC. In vitro ubiquitination experiments proved that TaRING1 could ubiquitinate TaRIP92. Transient expression of Nicotiana benthamiana and wheat protoplast transformation showed that TaRIP92 protein was localized in mitochondria. 【Conclusion】 TaRING1 interacts with mitochondrial protein TaRIP92 and ubiquitinates it.

Cloning and Cold Resistance Functional Analysis of Bog Bilberry E3 Ligases VuARI2 Gene

ZHANG Runmei, WU Fengzhang

2024,44(9):1420-1432 DOI: 10.7606/j.issn.1000-4025.20240169

[Abstract] (10) [HTML] (0) [PDF 13.61 M] (1991)

Abstract:
[Objectives] plant E3 ligases family has been recognized for its involvement in regulating plant responses to low temperature stress，its role in bog bilberry under low temperature stress remains largely unexplored. In this study，we cloned VuARI2 gene，transformation model plants Arabidopsis thaliana to explore the function of VuARI2 gene in responses to low temperature stress. [Methods] VuARI2 gene was cloned from stem of bog bilberry by RACE and RT-PCR and conducted a comprehensive bioinformatics analysis. Expression of VuARI2 in different tissues and stems and flower buds after cold acclimation were analyzed by qRT-PCR. Furthermore，Heterologously express the VuARI2 in Arabidopsi Thaliana，and the transgenic plants were analyzed for the expression levels of VuARI2，physiological indexes，and freezing resistance after cold acclimation. [Results] VuARI2 was successfully cloned，and its open reading frame of 1770 bp，which encoded 589 amino acids. The multi-sequence alignment and phylogenetic tree analysis of VuARI2 amino acids indicated that VuARI2 protein was closely related to ARI2 protein in wild camellia，coffee tree，grape and riverside grape. RT qPCR showed that the expression of VuARI2 in leaves and flower buds of bog bilberry was significantly higher than that in roots and stems，and the expression of VuARI2 in stems and flower buds was significantly induced by low temperature. After cold acclimation，expression levels of VuARI2 gene in transgenic plants was significantly higher in wild type，chlorophyll content decreased significantly lower than that of the wild type；proline content and soluble sugar content were significantly higher than that of the wild type；superoxide dismutase activity；peroxidase activity and catalase activity were significantly higher than that of the wild type；while relative conductivity and malondialdehyde content were significantly lower than that of the wild type. After cold acclimation，the survival rate of transgenic plants was significantly higher than that of the wild type，and the relative conductivity was significantly lower than that of the wild type at freezing temperature，significantly enhance the freezing resistance of plants. [Conclusions] Cloning and obtaining VuARI2-overexpressed A. thaliana plants，functional analysis showed that overexpress of VuARI2 gene could significantly enhance the cold resistance of plants.

Identification, evolution, and expression analysis of GH3 gene family in kidney bean

ZHANG Xiaoxu, MA Yuanyuan, LUO Xinrui, QIN Yaoxin, MA Tianyu, WANG Yuping

2024,44(9):1433-1444 DOI: 10.7606/j.issn.1000-4025.20240131

[Abstract] (8) [HTML] (0) [PDF 7.75 M] (1993)

Abstract:
[Objective] The Gretchen Hagen 3 (GH3) gene family is a class of auxin early response genes, which play an important role in plant growth and development and stress resistance. The objective of this study was to investigate the function and effect of GH3 gene in kidney bean. [Methods] The whole genome of kidney bean GH3 gene family was identified by bioinformatics and the expression of PvGH3 gene was detected by transcriptome data (RNA-seq) and fluorescent quantitative PCR (RT-qPCR) under different stress conditions. [Results] A total of 19 gene family members were identified in kidney bean, of which 17 genes were unevenly distributed on 8 chromosomes, and the other 2 genes could not be accurately located on scafford. Phylogenetic analysis divided the PvGH3 gene family into three subfamilies, and the members of each subfamily had similar gene structure and conserved motifs. The collinearity analysis showed that there were 3 para-homologous gene pairs between PvGH3 family members, and 15 direct homologous gene pairs between PvGHs and Arabidopsis GH3.Cis-element analysis showed that PvGH3 gene family contains cis-elements related to light, hormone, stress and growth and development. Tissue expression analysis showed that PvGH3 gene family was highly expressed in flowers, roots, buds and stems. qRT-PCR analysis showed that 19 PvGH3 were up-regulated in response to drought (6% PEG), salt (100 mmol/L NaCl) and low temperature (4 ℃) stress. PvGH3.19 was significantly responsive to drought stress, PvGH3.17 was responsive to salt stress. PvGH3.11 responds to low temperature stress. [Conclusion] In this study, 19 PvGH3 genes were identified in kidney bean. Their physicochemical properties, chromosomal location, collinearity, evolutionary relationship, conserved motif, cis-element and tissue expression were analyzed, and their functions and effects were further demonstrated by qRT-PCR. This study provided a theoretical basis for the analysis of resistance function of PvGH3.

Analysis of Codon Preference in Chloroplast Genomes of Four Zygophyllum Species

ZHANG Ling

2024,44(9):1445-1455 DOI: 10.7606/j.issn.1000-4025.20240273

[Abstract] (10) [HTML] (0) [PDF 3.14 M] (1984)

Abstract:
[Objective]In order to analyze the codon usage bias of the chloroplast genome of four Zygophyllum species, the study analyzed the codon composition and codon usage bias of 40 selected gene-coding sequences and identified the optimal codons.[Methods] The parity preference (PR2-plot) analysis, effective number of codons (NEC-plot), neutrality plot and RSCU cluster analysis of 40 genes from four Zygophyllum species were carried out using CodonW 1.4.2 and Emboss software in this study. [Results]The codon usage patterns in four Zygophyllum species plastomes were similar, and the GC content of codon was followed by GC1> GC2> GC3, the average ENC values were more than 35, and the CAI was 0.17, indicating the chloroplast genome gene expression level of Zygophyllum species was low and a weak codon preference. The results of neutral mapping analysis, ENC-plot selection and PR2-plot analysis showed that the codon usage pattern was affected by natural selection, which played a dominant role. RSCU cluster analysis showed that Z. fabago, Z. obliquum, Z.xanthoxylum and Z. kaschgaricum had 19, 13,14 and 14 optimal codons. By constructing the high and low gene expression library of the target genes, a total of four optimal genes were finally selected using totally the A\U ending.[Conclusion] The codon bases of chloroplast genome from four Zygophyllum species mostly ended with A\U. The codon usage bias of chloroplast genome have a weak codon preference, and be in?uenced by base mutations . Four optimal codons were identi?ed in this study, and the presence of few optimal codons may better understood the codon optimization, preference mechanism and genetic evolution relationship in Zygophyllum.

Study on micropyle closure in Platicladus orientalis and implications of biological evolution

SHANG Xin, ZHU Xiaoying, JIA Zhishuo, ZHANG Xin

2024,44(9):1456-1463 DOI: 10.7606/j.issn.1000-4025.20240087

[Abstract] (9) [HTML] (0) [PDF 5.08 M] (1995)

Abstract:
【Objective】 In order to enrich the data for the study of micropyle closure in gymnosperms and to provide a reference for the phylogenetic study of gymnosperms, the micropyle closure of Platicladus orientalis Franco was investigated.【Methods】 Female cones of Platycladus orientalis were sampled and examined using morphological techniques, including paraffin sections and scanning electron microscopy. Furthermore, cluster analyses based on the mode of micropyle closure were also conducted for Bennettitales.【Results】 (1) After the pollen of Platicladus orientalis enters the ovule, the innermost two cell layers of the integument begin to grow radially inward until the micropyle is completely closed. (2) During the micropyle closure of Platicladus orientalis, the innermost cells of the integument are elongated and conical in shape, with the cell layers typically increasing to around 4 to 6 layers. (3) The micropyle closure of gymnosperms can be divided into four clades. These groups include one for Cycas and Ginkgo, another for Pinus and Podocarpaceae, a separate group for Bennettitales, and a cluster consist of Platycladus orientalis and other species. 【Conclusion】 The micropyle closure of Platicladus orientalis is differ with Ginkgo and cycads. while is similar with Pinus and Bennettitales. This study suggested that evolutionary relationship in micropyle closure between Bennettitales and extant conifers, providing novel morphological evidence for understanding the evolution of gymnosperm reproductive systems.

Biological Characteristics and Breeding System of Primrose Chicory Pollen in Primulina guizhongensis

HUANG Jiajun, XIE Meishi, JIANG Guiyun, LIU Juanxu, YU Yixun

2024,44(9):1464-1473 DOI: 10.7606/j.issn.1000-4025.20240004

[Abstract] (16) [HTML] (0) [PDF 4.74 M] (2007)

Abstract:
【Objective】To investigate the pollen biology characteristics of Primulina guizhongensis and the influence of the breeding system on its sexual reproduction, uncovering its reproduction mechanism and providing theoretical references for the conservation and development of Primulina.【Methods】Using P. guizhongensis as the material, we observed the floral characteristics of P. guizhongensis, screened the pollen isolation medium and the best pollen pollen viability detection method, explored optimal pollen storage conditions, determine the type of its breeding system.【Results】(1) P. guizhongensis dichogamy, stamens ripening before pistils; herkogamy, pistils higher than stamens (2) The optimum medium formulation for the culture of isolated pollen germination is 40 mg/mL boric acid + 10% sucrose + 7 g/L agar for two hours. (3) Pollen maintained a high germination rate after 7 d of storage at both -20°C and -80°C (4) The stigmas of P. guizhongensis are most fertile at 2-4 d of flowering. (5) P/O is 518.36~782.75, OCI is 5. (6) P. guizhongensis has a high self-fertilisation affinity and is unable to undergo fusionless reproduction.【Conclusion】 The in vitro germination method is the most intuitive and accurate way to detect pollen viability, low temperatures are conducive to pollen storage of P. guizhongensis, and the breeding system is predominantly heterogametic.

Pollination Biology of Ottelia acuminata and Ottelia acuminata var. crispa and Their Hybrid Affinity Studies

LI Junfeng, GAO Hongcan, YIN Genshen, LIANG Ziyu, YANG Xiaohong, ZHAI Shuhua

2024,44(9):1474-1481 DOI: 10.7606/j.issn.1000-4025.20230824

[Abstract] (11) [HTML] (0) [PDF 6.05 M] (1986)

Abstract:
【Objective】To unveil the pollination characteristics of the Chinese endemic rare and endangered aquatic plants Ottelia acuminata and Ottelia acuminata var. crispa, to investigate their adaptive relationship with pollinators, to elucidate the factors affecting the success of pollination, and to provide theoretical and technological guidance for the hybrid breeding of the two species；the study of hybrid affinity between the two not only provides insights into their cross-breeding dynamics but also serves as a valuable reference for broader studies involving cross-breeding and germplasm conservation within the genus.【Methods】Ottelia acuminata and Ottelia acuminata var. crispa were used as research subjects to study their pollination characteristics and hybrid affinity by observing their flowering dynamics, insect flower-visiting behaviors, determining pollen viability, stigma pollinability, and bagging test.【Results】The flowering dynamics of Ottelia acuminata and Ottelia acuminata var. crispa were basically similar, with single-flowering periods of 7-11 h. The main flower-visiting insects of both species are Episyrphus balteatus, Apis cerana, Bombus sp. and Coccinella sp；The trend of pollen viability and stigmatic accessibility of the two plants was consistent, both showed an increasing and then decreasing trend, Ottelia acuminata pollen viability was the highest at 88.27%, Ottelia acuminata var. crispa pollen viability was the highest at 88.34%, and stigmatic accessibility of both plants was the highest in the anthesis Ⅱ；The fruit set rate of Ottelia acuminata and Ottelia acuminata var. crispa orthologous and backcrosses were 85.71% and 91.33%, respectively, and the hybrid affinity indexes were above 53, which proved that there was no hybridization between Ottelia acuminata and Ottelia acuminata var. crispa. The average number of seeds in hybrid single fruit was 54, 69, 73, 71 and 71 respectively; Among the hybrid combinations, Ottelia acuminata (♂) × Ottelia acuminata var. crispa (♀) combination had the highest thousand-grain weight of 3.334 g. Seeds of the hybrid combinations were subjected to germination experiments, and it was concluded that the Ottelia acuminata (♂) × Ottelia acuminata (♀) combination had the seed germination rate was the highest, 71.7%, and the other three combinations, the germination rate was lower, with an average of 23.2%.【Conclusion】Ottelia acuminata and Ottelia acuminata var. crispa have basically similar flowering dynamics, with shorter single-flowering periods and fewer pollinator species, which affects their sexual reproduction; hybridization experiments between the two showed no significant hybrid discordance.

Cytological Observations on the Fertilization of the Fern Lygodium japonicum

SUN Rui, CAO Jianguo, DAI Xiling

2024,44(9):1482-1487 DOI: 10.7606/j.issn.1000-4025.20240275

[Abstract] (10) [HTML] (0) [PDF 4.04 M] (25)

Abstract:
【Objective】The fertilization of the fern Lygodium japonicum are observed 【Methods】using electronic. 【Results】The results indicated that: ① Lygodium japonicum do not have the typical egg envelope and fertilization pore, and spermatozoa penetrates the egg through the pore region. ② The first spermatozoon entered the cytoplasm of the egg, and 2-6 spermatozoa could also pass through the pore region to enter the fertilization cavity below the pore region of the egg, but could not fuse with the egg cytoplasm. ③ After the sperm enters the egg, the fertilized egg shrinks markedly to prevent the entry of other sperm, and a membrane structure is formed at the location of the pore region above the fertilization cavity, which also plays a role in blocking the entry of other sperm into the fertilization cavity. ④ Nuclear fusion was initiated 30 min after spermatozoa entered the egg cell. The nucleus of spermatozoa was initially concentrated at one end of the egg nucleus and gradually penetrated into the nucleus of the egg, and nuclear fusion continued as the fertilized egg expanding. ⑤ Around 10 h after fertilization, the zygote produces a large number of vesicles, which first establish horizontal polarity and then change to vertical polarity, and undergo the first division of the zygote. 【Conclusion】When Lygodium japonicum undergoes fertilization, spermatozoa enter from the pore region and produce a fertilization cavity, which is similar to the core leptosporangiatae.

Response of plant community structure and soil water conservation function to forbidden grazing and enclosure in alpine steppe on the Qinghai Lake

ZHANG Li, GUO Longxin, ZHANG Mingyang, LI Xiaojuan, ZHAO Liang, YANG Yongsheng

2024,44(9):1488-1498 DOI: 10.7606/j.issn.1000-4025.20240030

[Abstract] (7) [HTML] (0) [PDF 1.74 M] (43)

Abstract:
【Objective】 Explore the impact of grazing enclosure on plant community structure and soil water conservation function of alpine steppe on the Qinghai Lake region, and It is significant to accurately evaluate the effect of grazing enclosure on the restoration of degraded grassland in Qinghai Lake. 【Methods】 Four sample plots (free-grazing, enclosure for 4 years, enclosure for 7 years and enclosure for 14 years) were set in the alpine steppe on the north shore of Qinghai Lake and the effects of enclosure measures on the number of vegetation species, biomass, functional groups, soil bulk density, water holding capacity and porosity was analyzed by the combination of field monitoring and indoor experiments in present research. 【Results】 (1) With the increasing of enclosure times, the number of species in the alpine steppe on the north shore of Qinghai Lake was decreased, the vegetation cover, above-ground biomass, below-ground biomass was first increased and then decreased. The percentage of grasses in the community gradually increased, which improved the feeding value of plant on the north shore of Qinghai Lake. (2) The effects of grazing exclusion on soil moisture characteristics of alpine steppe on the north shore of Qinghai Lake are mainly concentrated in the 0-20 cm depth. With the extension of grazing exclusion years, soil bulk density at 0-20 cm decreased gradually, soil saturated water holding capacity, capillary water holding capacity, field water holding capacity and total porosity at 0-10 cm first increased and then stabilized. (3) Soil bulk density is the most important soil water characteristic factor which affecting the vegetation community structure on the alpine steppe in the north shore of Qinghai Lake. 【Conclusion】 Short-term grazing exclusion measures are conducive to the recovery of degraded grassland ecosystems along the north shore of Qinghai Lake, and it was an effective measures to improve the degradation of grasslands in this area, but scientific grazing exclusion should be carried out to avoid prolonged grazing exclusion.

Floristic analysis of stone pine and fern in Tingjiangyuan Nature Reserve, Fujian

ZHANG Xiuhua, ZHONG Yixin, PENG Donghui

2024,44(9):1499-1508 DOI: 10.7606/j.issn.1000-4025.20230609

[Abstract] (365) [HTML] (0) [PDF 509.56 K] (1057)

Abstract:
Abstract: Based on field investigation and compilation of the list of stone pine and fern resources of Tingjiangyuan National Nature Reserve in Fujian, the flora composition of the area was statistically analyzed by using the principle of flora geography, and compared with the flora of the four neighboring protected areas. The results showed that: (1) There were 129 species of lycopodians and ferns in 23 families, 60 genera, including 3 rare and endangered species. There were 3 families, with a total of 61 species in 23 genera, accounting for 47.29% of the total species. There is 1 genus, a total of 11 species, accounting for 8.53% of the total number of species, and the composition of families and genera is obvious. Monofamilies and oligofamilies accounted for 65.21% of the total family, and monospecies and oligogenera accounted for 90.00% of the total number of genera. (2) In terms of distribution area, tropical components accounted for 100% of the total number of families; Tropical components accounted for 84.21% of the total genus; Tropical component species accounted for 52.85%, temperate component species accounted for 35.25%, mainly tropical Asian distribution species, followed by East Asia and its variants. There are 15 species endemic to China. The tropical attributes of this area are predominant, the tropical relatives are obvious, and there are certain temperate properties. (3) The comparison with the geographical composition of the flora of neighboring protected areas showed that in terms of similarity coefficients of families, genera and species, Tingjiangyuan and the four protected areas reached more than 85%, 74% and 50%, respectively. The germline differentiation degree of 4.75 in this area is similar to that of Liangyeshan 4.69, which is relatively low. In terms of geographical affinity, the stone pine and fern fauna in this area have the highest connection with Liangye Mountain, and the closest kinship is the same, and the kinship relationship with Matou Mountain in Jiangxi is relatively distant.

Cloning and heat tolerance analysis of the thermomorphogenesis gene KcPIF4 in Karelinia caspica

HUANG Wanyi, LI Wenlong, WANG Yanqin

Available online:August 21, 2024, DOI: 10.7606/j.issn.1000-4025.20240227

[Abstract] (38) [HTML] (0) [PDF 5.39 M] (110)

Abstract:
[Objective] The desert plant Karelinia caspica exhibits extremely strong heat tolerance. Cloning and studying heat-tolerant genes from Karelinia caspica, and applying them to economically important crops such as cotton to enhance their heat tolerance, aims to provide a theoretical basis and genetic resources for molecular breeding of heat tolerance in crops.[Methods] Clone the KcPIF4 gene from Karelinia caspica and conduct bioinformatics analysis; Transient expression analysis in tobacco for subcellular localization of the protein; use qRT-PCR to analyze the expression levels of KcPIF4 in the roots, stems, and leaves of Karelinia caspica seedlings at 45°C for 5 min, 30 min, 120 min, and 240 min; observe phenotypic changes in Arabidopsis thaliana overexpressing KcPIF4 under 45°C treatment and measure related physiological and biochemical indicators. [Results] The full-length coding sequence of the KcPIF4 gene in Karelinia caspica is 1 593 bp, encoding 530 amino acids, with a conserved bHLH domain and differences in motifs compared to homologous proteins in various plants. The protein was localized on the guard cell membrane of leaf stomata. The qRT-PCR results indicate that the expression level of KcPIF4 in the leaves of Karelinia caspica initially increases, then decreases, and subsequently increases again with the extension of treatment time. At 240 minutes, the expression level is the highest, being 4.4 times higher compared to the control group. Arabidopsis plants overexpressing KcPIF4 under 45°C treatment showed less leaf yellowing and wilting compared to the wild type, with significantly higher levels of CAT, SOD, POD, chlorophyll a, chlorophyll b, and carotenoids, and significantly lower levels of MDA and relative conductivity compared to the wild-type. [Conclusion] The KcPIF4 exhibits a process of tolerance-response-adaptation to high temperature stress, enhancing Arabidopsis thaliana"s tolerance to high temperatures, indicating that this protein possesses heat tolerance.

Chloroplast Genome Structure Characteristic and Phylogenetic Analysis of Berberis diaphana Maxim

REN Yuling, LI Xinger, LIANG Jialing, ZHAO Shaung, ZHAO Chengzhou, LI Ping

Available online:August 21, 2024, DOI: 10.7606/j.issn.1000-4025.20240222

[Abstract] (60) [HTML] (0) [PDF 5.27 M] (107)

Abstract:
[Objective] In order to clarify the structural features of the chloroplast genome of Berberis diaphana and the phylogenetic relationship with the taxa of the same genus, we comprehensively analyzed its chloroplast genome structure characteristics and phylogenetic. [Methods] Sequencing was performed by Illumina Hiseq X Ten technology, and the chloroplast genome characteristics of Berberis diaphana were analyzed by using CPGview, CodonW, MISA, Reputer, IRscope, and mVISTA software, and phylogenetic tree was constructed by ML method in MEGA7 software. [Results] The results showed that the chloroplast genome of Berberis diaphana have a length of 166 225 bp, with a typical quadripartite structure and the GC content of the whole genome was 38.07%. A total of 144 genes were annotated, including 99 protein coding genes, 37 tRNA genes, and 8 rRNA genes. Among them, 23 genes contained introns, and 32 genes were present in duplicate copies. Preference for codons ending in A/U. A total of 98 SSR loci and 150 scattered repeat sequences were detected, and most SSR loci composed of A/T bases. The degree of variation in the SSC and IR regions was higher than that in the LSC region. Phylogenetic analysis revealed that Berberis diaphana was most closely related to Berberis weiningensis. [Conclusion] The chloroplast genome structure characteristics of B. diaphana are similar to other species of berberis, which can serve as a theoretical basis for studies on chloroplast genetic engineering, genetic diversity analysis, molecular breeding, and species identification.

Cloning and Functional Validation of PdMYB57 from Paeonia delavayi

DU Chun, PING Huailei, LIU Siqi, LI Haiqing, TONG Haizhen, WANG Juan

Available online:August 21, 2024, DOI: 10.7606/j.issn.1000-4025.20240141

[Abstract] (65) [HTML] (0) [PDF 6.54 M] (113)

Abstract:
Abstract [Objective] As a precious peony breeding material, Paeonia delavayi has abundant flower color resources. Studying the regulatory effect of its MYB transcription factors on flower color can provide assistance for molecular breeding of peony flower color. [Methods] Using the flower tissue of yellow and red P.delavayi as materials, observing the distribution characteristics of anthocyanins in its cells through hand sectioning. Based on the transcriptome data of the two materials, a MYB transcription factor PdMYB57 was obtained through sequence alignment. The physicochemical properties and functions of the PdMYB57 transcription factor were predicted through gene cloning, bioinformatics analysis, phylogenetic tree, and homologous sequence alignment. Subsequently, Quantitative reverse transcription polymerase chain reaction (qPCR), transient expression in tobacco, and High performance liquid chromatography (HPLC) were used to validate the function of PdMYB57. [Results] The PdMYB57 gene has a complete open reading frame of 798 bp, encoding 265 amino acids, and is located in the nucleus as a hydrophilic unstable protein; Cluster together with the SG6 subfamily in the R2R3MYB family of Arabidopsis, as well as MYB transcription factors that promote anthocyanin synthesis in P.qiui PqMYB113,P.suffruticosa PsMYB57/PsMYB58 and Vitis vinifera VvMYBA1/VvMYBA2, and exhibit a typical R2R3 conserved domain [R/K] Px [P/A/R] xx [F/Y] motif; the qPCR results showed that the PdMYB57 gene has high expression levels in the sepals of red P. delavayi and leaves of yellow P. delavayi. In other tissues, the expression level is extremely low and almost non-existent, which is consistent with the transcriptome data results; HPLC detection showed that the tobacco leaves with transient expression of the PdMYB57 gene contain Cyanidin- 3-O-rutinoside (Cy3R) , while the tobacco leaves with CK control did not produce color and Cy3R was not detected in the extraction solution. [Conclusion] The PdMYB57 gene encodes an R2R3-MYB transcription factor, located in the nucleus as a hydrophilic unstable protein. Its expression is tissue-specific and promotes the synthesis of anthocyanins in plants.

Analysis of the response of tetraploid Citrus wilsonii Tanaka to drought stress based on phosphoproteomics

DENG Xixi, REN Kexin, WEI Lina, WANG Haotian, HU Jia, JIANG Jinglong

Available online:August 21, 2024, DOI: 10.7606/j.issn.1000-4025.20240086

[Abstract] (42) [HTML] (0) [PDF 3.23 M] (119)

Abstract:
[Objective] Based on the phosphoproteomics, the expression patterns of proteins phosphorylated were analyzed in tetraploid Citrus wilsonii leaves under drought stress to reveal its response mechanism at the molecular level. [Methods] Phosphorylated proteins in the leaves of tetraploid Citrus wilsonii after drought stress were identified and analyzed using IMAC affinity enrichment and TMT labeling technology. Functional annotation and metabolic pathway analysis of differentially expressed proteins with phosphorylated were also performed. [Results] (1) A total of 3 794 phosphorylation sites and 1 521 phosphorylated proteins were quantified. There were 662 phosphorylated proteins with a fold change exceeding 1.3(αFC>1.3), which mainly located in the nucleus (46.07%) and chloroplasts (24.62%). (2) The differentially expressed proteins with phosphorylated mainly played roles by binding RNA and Ca2+ and participated in metabolic pathways such as RNA splicing, photosynthesis, SNARE interaction in vesicle transport. (3) RT-qPCR results showed that 92.86% genes of differentially expressed proteins with phosphorylated had a consistent trend of change in transcriptional and protein levels and the pearson correlation coefficient was 0.893. [Conclusion] Tetraploid Citrus wilsonii regulated the proteins involved in RNA splicing and photosynthesis pathways through phosphorylation to respond to the drought stress.

Correlation analysis between physical characteristics and seed vigor of the endangered plant, Abies beshanzuensis

LV Hongfei, LOU Chenkun, LAN Rongguang, XIONG Yanyun, YANG Yunfang, YU Mingjian

Available online:August 20, 2024, DOI: 10.7606/j.issn.1000-4025.20240230

[Abstract] (65) [HTML] (0) [PDF 1.18 M] (115)

Abstract:
[Objective] Exploring the relationship between the morphological characteristics and physical characteristics of the seeds of Abies beshanzuensis and their seed vigor, providing a theoretical basis for further population renewal and protection of this endangered species, explaining its endangered mechanism, and studying its seed biology. [Methods] Using the critically endangered plant A. beshanzuensis as the research material, the characteristic constants of the length, width, thickness, single grain mass, RGB, etc. of the seeds of A. beshanzuensis were measured. The seed vigor was determined using TTC staining method, and their mathematical models were established. [Results] There was a significant correlation between the R, B value, and single seed mass of A. beshanzuensis seeds and seed vigor, respectively. Single factor linear regression analysis showed that the correlation between seed vigor and single seed mass of A. beshanzuensis was the most significant, with R2=0.839. Two factor linear regression analysis showed that the seed vigor had the most significant correlation with single seed mass and thickness, with R2=0.928. Multivariate linear regression analysis, R2=0.978. However, there was no significant correlation between the length, width, thickness, and G value of its seeds and seed vigor, respectively. [Conclusion] By using indicators such as R, B value, and single grain mass of A. beshanzuensis seeds, seeds with higher seed vigor can be screened. Multiple factor linear regression analysis can more accurately predict their seed vigor.

#$NPOptimization of determination methods for major triterpenoid compounds in Centella asiatica (L.) Urban

YANG Ruomeng, TIAN Jun, LI Yunzhe

Available online:August 20, 2024, DOI: 10.7606/j.issn.1000-4025.20240277

[Abstract] (36) [HTML] (0) [PDF 1.49 M] (113)

Abstract:
[Objective] To provide a basis for quality control of Centella asiatica (L.) Urban, a high-performance liquid chromatography method using cyclodextrin as a mobile phase additive for the determination of asiaticoside, asiaticoside B and madecassoside was established. [Methods] Molecular design was used to optimize the type of the mobile phase additive-cyclodextrin. The response surface method was used to analyze the effects of cyclodextrin concentration, the proportion of acetonitrile in the mobile phase, and pH of the mobile phase on separation, and optimize the chromatographic condition. The optimized chromatographic condition was used to determine the content of asiaticoside, asiaticoside B and madecassoside in C. asiatica. [Results] γ- cyclodextrin was used as a mobile phase additive. The separation of asiaticoside, asiaticoside B and madecassoside was carried out on CAPCELL PAK C18 (150 mm×4.6 mm, 5 μ m) with 3 mmol/L γ-cyclodextrin solution (contained 0.10% phosphoric acid)-acetonitrile (20∶80, V/V). The detecting wavelength was 205 nm. The flow rate was set at 1.0 mL/min and the column temperature was 25 ℃. The resolution of asiaticoside B and madecassoside is 4.32. Linearity was good in the range of 200~2 000 ng for asiaticoside, 120-1 200 ng for asiaticoside B and 200~1 200 ng for madecassoside. The precision, reproducibility, stability, and recovery rate of method were good. [Conclusion] This method is simple, accurate, reliable, and environmentally friendly, and can be used as a quality control of major triterpenoid compounds in Centella asiatica (L.) Urban.

Optimization of efficient virus elimination and regeneration system for shoot apical meristem culture of tea Chrysanthemum

SHI Ziyin, ZHANG Hainan, LI Hao, LV Jinhui

Available online:August 20, 2024, DOI: 10.7606/j.issn.1000-4025.20240175

[Abstract] (36) [HTML] (0) [PDF 1.46 M] (105)

Abstract:
[Objective] Screening suitable heat treatment duration and detoxification agents to optimize the efficient virus elimination and regeneration system of tea Chrysanthemum shoot apical meristem, addressing the issue of low rate of obtaining virus-free seedlings. [Methods] Six varieties of tea Chrysanthemum including "WuYuanHuangJu", "JinSiHuangJu", "HangBaiJu", "BeiJingJu", "QiYueXue", and "Ruhe" were used as materials. The axenic seedlings were pre-treated with alternating temperature heat treatment of 40°C/32°C day/night, detoxification agents such as salicylic acid, ribavirin, and abscisic acid, as well as a combination of detoxification agents and heat treatment. The rates of callus induction, regeneration frequency, and average number of regenerated shoots from inoculated shoot apical meristems were compared among different treatment methods, evaluating the detoxification efficacy under various treatments.[Results] (1) There was a significant difference in the regeneration frequency of shoot apical meristems among different varieties of tea Chrysanthemum (P<0.05), with "WuYuanHuangJu" having the highest regeneration frequency of 54.77%, followed by "JinSiHuangJu", "BeiJingJu", "QiYueXue", HangBaiJu and "Ruhe". (2) Under different heat treatment days, the difference in regeneration of shoot apical meristems in tea Chrysanthemum reached a significant level, with "HangBaiJu" and "QiYueXue" showing the best regeneration effect after 40℃/32℃ heat treatment. (3) Salicylic acid, Ribavirin, and Abscisic acid treatments inhibited the regeneration of shoot apical meristems. (4) Salicylic acid and ribavirin treatments combined with heat treatment promoted the regeneration of shoot apical meristems, while high concentration Abscisic acid combined with heat treatment severely inhibited the regeneration of shoot apical meristems. Treatment with 10 μmol/L Salicylic acid combined with heat treatment showed the best regeneration effect on shoot apical meristems. (5) Obtaining completely virus-free seedlings through heat treatment, the combined method of detoxification agents and heat treatment. [Conclusion] The combination of 10 μmol/L salicylic acid concentration with alternating temperature of 40°C/32°C day/night pre-treatment for 40 days significantly enhances the regeneration frequency of shoot apical meristems and results in obtaining virus-free seedlings.

Analysis of antioxidant enzyme activity and related gene expression of two ploidy Camellia reticulata species under low temperature stress

FU Xian, YONG Qingqing, ZHOU Lin, WANG-WEI Qinlan, QU Yan

Available online:August 16, 2024, DOI: 10.7606/j.issn.1000-4025.20240245

[Abstract] (45) [HTML] (0) [PDF 2.25 M] (131)

Abstract:
【Objective】 Camellia reticulata is the first of the eight famous flowers with evergreen leaves and bright colors, but its cold tolerance is poor. This paper discusses the cold tolerance of two ploidy Camellia reticulata from the physiological and molecular levels, which can provide references for the mining of cold tolerance genes and molecular breeding of Camellia reticulata. 【Methods】 Using tetraploid (4X) and hexaploid (6X) annual seedlings of wild Camellia reticulata as experimental materials, physiological indexes and transcriptome sequencing of leaves of Camellia reticulata. were determined after low temperature (-4℃) stress treatment (0 h, 24 h, 72 h, reheated for 48 h and reheated for 72 h). 【Results】 From the observation of leaf phenotype, from the stress period to the rewarming period, the damage degree of hexaploid leaves was relatively small, and the cold resistance performance of hexaploid leaves was better than that of tetraploid leaves. According to the results of physiological indexes, except MDA and GSH, the accumulation of other physiological indexes of hexaploid was greater than that of tetraploid. Correlation analysis of antioxidase activity and its differential genes showed that 5 and 7, 7 and 17 genes were significantly correlated with GSH content and POD activity in tetraploid and hexaploid, respectively, and only 2 genes in hexaploid were significantly correlated with SOD activity. 【Conclusion】 Hexaploid is more effective than tetraploid in alleviating the damage of plants under low temperature stress. Antioxidase-related genes may be involved in the regulation of low temperature by regulating their activity.

Configuration and Photosynthetic Characteristics of Chinese Cabbage Cultivated in Continuous Cropping Soil

XU Lei, YE Lin

Available online:August 16, 2024, DOI: 10.7606/j.issn.1000-4025.20240194

[Abstract] (65) [HTML] (0) [PDF 1.50 M] (114)

Abstract:
【Objective】To explore the effects of different application methods of compound bacterial agents on the growth, root morphology and photosynthetic characteristics of Chinese cabbage seedlings, so as to provide theoretical basis for the relieving effect of compound bacterial agents on the continuous cropping obstacle of Chinese cabbage. 【Methods】Three kinds of compound fungi application methods, T1 (foliar spraying), T2 (soil application) and T3 (foliar spraying + soil application), were set up with CK (no compound fungi application) as control.【Results】Compared with CK, T1 treatment significantly increased plant height, stem diameter and root length by 91.81%, net photosynthetic rate by 24.55%, Fv/Fm and ΦPSII by 5.70% and 23.93%, respectively. Correlation showed that each index had a strong relationship. By principal component analysis, 23 single indexes were converted into 3 independent comprehensive indexes, and the cumulative contribution rate could reach 85.399%. The comprehensive weight values of ΦPSII, qp, fresh weight of underground part, Fv/Fm, number of root connections, and plant height were relatively high. Conclusion: Foliar spraying compound bacterial agent is the best way to promote seedling growth, improve root configuration and enhance photosynthesis in continuous cropping of Chinese cabbage, and it is the best way to apply compound bacterial agent.

Flowering phenology characteristics and climate adaptability of ornamental crabapple

LI Shuqing, ZHANG Wangxiang, SHEN Yiqian

Available online:August 16, 2024, DOI: 10.7606/j.issn.1000-4025.20240154

[Abstract] (59) [HTML] (0) [PDF 1.64 M] (133)

Abstract:
Abstract：【Objective】Ornamental crabapple is an excellent spring flowering tree species. Studying its flowering phenology characteristics, stability and change rules, and exploring its relationship with climate change are of great significance for the prediction and regulation of the flowering period of crabapple in the future.【Method】Based on the phenological observation data of 67 varieties for 8 years, the flowering date, length and stability of crabapple were divided, and the adaptability of each variety to climate change was analyzed in combination with meteorological data.【Result】(1) The stability of the initial flowering time of the crabapple variety group was high, and the fluctuation range of the initial flowering time of most varieties (68.7%) was 0-0.04. (2) The flowering life of crabapple is highly sensitive to climate, and only some varieties (18%) have a relatively stable flowering length, with a fluctuation range of 1-2. (3) Ornamental crabapple flowering requires a certain low temperature stimulation, and different varieties have different low temperature requirements for flowering. (4) When the daily maximum temperature≥25℃, daily precipitation≥5mm or daily relative humidity≥80%, the flowering period of crabapple will be shortened.【Conclusion】Low temperature before flowering can significantly affect the stability of the initial flowering period of crabapple, and maintaining a suitable climate during flowering is of great significance for prolonging the flowering period of crabapple.

Genetic diversity of Gossypium barbadense germplasm resources and identification of resistance to Verticillium wilt

Jiang Mengzhu, Yang Yuzhe, Lv Tao, Qu Yanying, Chen Quanjia, Zheng Kai

Available online:August 16, 2024, DOI: 10.7606/j.issn.1000-4025.20240150

[Abstract] (19) [HTML] (0) [PDF 7.44 M] (141)

Abstract:
Abstract 【Objective】 Through the joint identification and analysis of disease resistance in the field and indoor seedling stage, the distribution of disease resistance of gossypium barbadense germplasm resources was mastered, which provided a basis for screening high resistance resources to Verticillium wilt. 【Methods】 The 238 gossypium barbadense germplasm resources of our research group were used as identification objects. In 2023, the natural disease field plot test was carried out in KEL and AWT, and the resistance of gossypium barbadense resources to Verticillium wilt was identified and evaluated by indoor inoculation. 【Results】 The genetic diversity of 15 indexes of 238 gossypium barbadense germplasm resources was analyzed. The coefficient of variation ranged from 2. 00 % to 36. 97 %, with an average of 16. 05 %. Resistance identification in different environments showed that the coefficient of variation ranged from 8.40 % to 71.06 %. Based on the analysis of four different environments, no germplasm resources with complete immunity and high resistance to Verticillium wilt were identified, and 30 resistant materials, 194 resistant materials and 14 susceptible materials were identified. 【Conclusion】 The overall trend can be seen that most of the gossypium barbadense planting resources have resistance to Verticillium wilt. Therefore, it is very important to identify and select germplasm resources with strong resistance to Verticillium wilt from gossypium barbadense germplasm resources.

Analysis of Flowering Characteristics and Floral Aroma Components Release Pattern of Rhus chinensis Mill

GU Ju, WEN Lianhao, NIU Yun, PU Yufan, WU Yandi, WANG Chao

Available online:August 16, 2024, DOI: 10.7606/j.issn.1000-4025.20240125

[Abstract] (20) [HTML] (0) [PDF 2.27 M] (119)

Abstract:
[Objective]This study intends to clarify the material basis of flower fragrance by exploring the flowering characteristics, flower fragrance components and their release patterns of Rhus chinensis, so as to provide a basis for the further development and utilization of the floral fragrance of Rhus chinensis. [Methods]Scanning electron microscope was used to observe the pollen morphology, and Headspace-solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) techniques were used to detect and analyze the main floral scent components in different flowering stages and the daily change pattern.. [Results]Dioecious plant of Rhus chinensis, panicle, single branch inflorescence concentrated flowering, whole plant in continuous bloom, pollen yellow, oblong-globose with 3 pore grooves, outer wall striped. A total of 92 floral substances (29 terpenes, 19 aldehydes, 15 esters, 14 alcohols, 5 ketones, 4 olefins, 2 aromatic hydrocarbons, and 1 each of phenols, alkanes, acids, and others) were detected in the different flowering periods. Its relative content increased and then decreased, reaching a maximum (3.60 μg/g) at the Full-flowering stage with significant differences among the flowers, and the species continued to increase. A total of 84 floral aroma substances were detected during the daily variation of its full flowering stage, and the releases showed a parabolic trend, which was significantly higher during the day than at night, and reached the maximum at 18:00 (4.80 μg/g), and then continued to decrease, and was the lowest at 6:00, with only 2.58 μg/g. Among them, terpenes were the main floral substances of Rhus chinensis, with a relative content of about 70% of the total floral components. [Conclusion]Rhus chinensis is rich in floral components, with a clear diurnal rhythm, and terpenes are its main floral substances.

Cloning and Expression Analysis of CaPEX3 in pepper

ZANG Qiao-Lu, LIU Lu, LIU Han, WANG Jing, WANG Meng, CHENG Yan

Available online:July 16, 2024, DOI: 10.7606/j.issn.1000-4025.20240216

[Abstract] (63) [HTML] (0) [PDF 13.48 M] (235)

Abstract:
[Objective] PEX (Pollen extensin-like) gene is involved in controlling pollen development，which plays a crucial role in the embryogenesis of pollen microspores and haploid culture. In this study, we isolated the CaPEX3 gene from pepper and analyzed its protein structure and expression pattern, which provides a theoretical foundation for further investigation into the function of the CaPEX3 gene. [Methods] CaPEX3 was cloned by PCR, and its protein structure, evolution and gene regulation were analyzed by bioinformatics. The expression of CaPEX3 in different tissues and pollens of different varieties were detected by qRT-PCR. The pollen viabilities of different varieties of pepper were detected by staining method and their relationships with the expression of CaPEX3 were analyzed. [Results] The coding region of CaPEX3 was 1 581 bp in length, encoding 526 amino acids, which belongs to the LRX (Leucine-rich Repeats/Extensins) gene family. The protein has phosphorylation, glycosylation sites, signaling peptides and transmembrane domains. The expression level of CaPEX3 was the highest in flowers, and the gene expression was higher in tissues with high pollen vitality. The regulatory network predicted that CaPEX3 may be involved in the regulation of pollen development through the action of genes related to flower development. [Conclusion] The expression of CaPEX3 was specifically localized to flowers, and a correlation was observed between its expression level and the activity of pollen grains. The analysis of gene expression and the construction of related vectors provide a theoretical foundation and technical support for the subsequent investigation of gene function and mechanism of CaPEX3.

Photosynthetic characteristics and anatomical structure of turnip seedling leaves in response to drought stress

HE Miao, MA Guocai

Available online:July 15, 2024, DOI: 10.7606/j.issn.1000-4025.20240160

[Abstract] (56) [HTML] (0) [PDF 8.65 M] (207)

Abstract:
[Objective] We aim to investigate the effect of drought stress on the photosynthetic characteristics and anatomical structure of turnip leaves, and to provide a basis for the selection and breeding of drought-resistant germplasm and the formulation of cultivation measures. [Methods] Drought-resistant and drought-sensitive turnip seedlings were selected, and normal water supply (control) and drought stress treatments were set up to analyze the changes in photosynthetic characteristics and anatomical structures of turnip seedlings' leaves through potting experiments. [Results] Compared with the control, drought stress significantly decreased the chlorophyll a, chlorophyll b and total chlorophyll contents, net photosynthetic rate, stomatal conductance, transpiration coefficient and stomatal limiting value of turnip leaves, and significantly increased the inter-cellular CO2 concentration and water-use efficiency; meanwhile, the initial fluorescence was significantly increased, and the maximal fluorescence, variable fluorescence, PS II maximal photochemical efficiency and PS II potential activity were significantly decreased, and the drought The changes were greater in drought-sensitive germplasm. Under drought stress, leaf stomatal length and width, stomatal openness, and stomatal density were significantly reduced; leaf thickness was significantly increased, and tissue laxity was significantly reduced; chloroplasts changed from pike-shaped to swollen, basal lamellae were fuzzy and hollow, osmiophilic granules and starch grains were increased, mitochondria were swollen and their internal cristae were fuzzy, and the two types of organelles were more seriously damaged in drought-sensitive germplasm. [Conclusion] Drought stress reduces the stomata of turnip leaves, increases the thickness of leaves, reduces the laxity of tissue structure, changes the morphological structure of chloroplasts and mitochondria, and then reduces the chlorophyll content and photosynthetic efficiency, and drought-resistant germplasm is less affected by the drought stress, and the adaptive regulation of drought stress is stronger.

Cloning and Analysis of Flowering Gene LFY from Early-maturing Rape (Brassica napus L.)

AI Yu-fang¹, CHEN Guan-shui¹, ZHOU Yi-fei², ZHANG Mei¹, 3, PAN Da-ren^1*

2012,32(10):1965-1970, DOI:

[Abstract] (5267) [HTML] (0) [PDF 3.06 M] (36428)

Abstract:
RG-8M,early-maturing mutant of late-maturing rape RG-8,was used in the present study.A LEAFY（LFY） homologue gene named BnLFY was cloned from RG-8M with the method of homologous cloning.The full length of BnLFY cDNA was 1 310 bp and contained a complete open reading frame of 1 248 bp,which encoded 415 amino acids residues.As other dicotyledon LFY-like proteins,the deduced amino acid sequence of BnLFY gene had several special regions such as N terminal proline rich region,the central acidic domain,the leucine zipper structure and the lysine and arginine-rich basic region.The result of sequencing indicated that the BnLFY protein shared more than 84% amino acid sequence identity with LFY-like proteins of several cruciferous plants.Transcriptional analysis showed the BnLFY gene expressed constitutively in rape.

Construction and phenotypic analysis of EMS mutant library of seed-used pumpkin (Cucurbita pepo L.)

SUN Mingyang, WANG Ping

2024,44(8):1283-1294, DOI: 10.7606/j.issn.1000-4025.20240121

[Abstract] (97) [HTML] (0) [PDF 10.06 M] (21550)

Abstract:
【Objective】To accelerate the innovation process of germplasm resources of seed-used pumpkin by constructing a mutant library, which is of great significance for variety selection, improvement and broadening of the genetic base. 【Methods】 Ethyl methanesulfonate (EMS), a 1.8% mutagen, was used to treat ZHL4 seeds of seed-used pumpkin for 15h. Then, phenotypic variation was observed in single plants of the M1 and M2 generation populations, and microstructural observation was made on the mutant strain ZHL4-33 of the M2 population. 【Results】 (1) A total of 242 mutant plants with 45 phenotypic variations were screened in the M2 population, and the types of variation covered all growth periods and plant organs of the mutant plants, with a total mutation frequency of 25.17%. (2) The leaf microstructure showed that the thickness of the fenestrated tissue of the mutant was significantly higher than that of the wild type, the arrangement was compact, and the traces of the vascular layer were obvious; the stem microstructure showed that the vascular bundles of the mutant were more and densely packed, the diameter of the conduit was smaller than that of the wild type, and the pith was well developed, with a small cell gap and an increase in the number of cells. 【Conclusion】 A mutant library of 425 M2 lines has been constructed, which lays a material foundation for the study of the functional genome of seed-used pumpkin and the selection and breeding of new varieties of seed-used pumpkin.

Induction of innate immune physiological responses in pepper seedlings by chitin and flg22

GONG Xuefeng, XU Yi, SONG Zhanfeng, CHEN Xin, CHEN Qiong, HOU Sihao

2024,44(8):1190-1200, DOI: 10.7606/j.issn.1000-4025.20230710

[Abstract] (443) [HTML] (0) [PDF 1.01 M] (20857)

Abstract:
[Objective] To clarify the characteristics of innate immune physiological responses induced by chitin and flagellin-derived peptide flg22 in pepper seedlings, and to explore the relationship between innate immune physiological responses and pepper multiple resistance to diseases. [Methods] Five local pepper cultivars from Sichuan were used as experimental materials in this study. The disease indexes of bacterial wilt and phytophthora blight in pepper seedlings were analyzed. Meanwhile seedlings were cultured by hydroponics and treated with chitin and flg22 exogenously. Among different pepper cultivars， under different induction times, seedling root growth, stomata aperture, callose deposition, reactive oxygen species (ROS) accumulation, SOD, CAT activities as well as the changes of related gene expression were checked . Then the physiological responses and theirs relationship with disease resistance were evaluated comprehensively by using biostatistics.[Results] (1) The results showed that the lowest disease index of bacterial wilt and phytophthora blight was 'CT10' cultivar, was the strongest disease resistance, and the highest disease index of bacterial wilt and phytophthora blight was 'TJ' cultivar, was the weakest disease resistance.(2) Exogenous chitin and flg22 inhibited the root growth rate of pepper seedlings in five cultivars, induced stomatal closure on detached leaves, promoted the accumulations of callose deposition in leaf cell wall, increased ROS content constantly with improved SOD and CAT activities continuously. By calculating the average membership function value of the innate immune physiological response index of each different cultivar, it showed that the highest was 'CT10' and the lowest was 'TJ'. The average membership function value has a significant negative correlation with the disease index of bacterial wilt and phytophthora blight .(3) Exogenous flg22 and chitin induced some innate immune involved genes of 'CT10' seedlings significantly upregulation expressions, like CaWRKY22, CaMAPK7 and ChiIV3.[Conclusion] Exogenous flg22 and chitin induced the innate immune physiological responses in pepper seedlings, and the strength of the responses showed different among different varieties. Based on the membership function, the disease resistance level of pepper varieties was evaluated comprehensively. The results showed the average membership function of 'CT10' was the highest and the multi-resistance level was the best, which was related to the significant up-regulated expression of innate immune involved genes CaWRKY22, CaMAPK7 and ChiIV3.

Effect of 2,4-epibrassinolide on the growth and physiological characteristics of common bean seedings under saline and alkaline stresses

Ma Yuanyuan, Wang Zhi, Cao Jinping, Luo Xinrui, Wang Yuping

2024,44(8):1181-1189, DOI: 10.7606/j.issn.1000-4025.20240138

[Abstract] (227) [HTML] (0) [PDF 945.50 K] (20364)

Abstract:
Abstract 【Objective】In order to explore the physiological mechanism of exogenous 2,4-epibrassinolide (2,4-EBR) in common bean (Phaseolus vulgaris L.) seedlings under saline-alkali stress conditions.【Methods】Using ''Shanxi Red Common Bean'' as the test material, we studied the effects of saline-alkali stress at 100mmol/L (50mmol/LNaCl+50mmol/LNaHCO3, XP), effects of exogenous spraying of 0.1 mg/L 2,4-EBR and 4.0 mg/L Brassinozole (BRZ) on the growth, photosynthetic gas parameters, antioxidant enzyme activity and osmotic adjustment substance content of common bean seedlings , and perform correlation and principal component analysis.【Results】Under saline-alkali stress, common bean leaves curled and withered, and plant height, leaf area, main root length, synthetic pigment content, net photosynthetic rate (Pn), transpiration rate (Tr), and stomatal conductance (Gs) all decreased significantly (P<0.05) , proline (Pro), soluble sugar (SS) content and superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbic acid peroxidase (APX) activities, Relative conductivity (REC), malondialdehyde (MDA) and intercellular carbon dioxide concentration (Ci) were significantly increased (P<0.05). Exogenous spraying of 2,4-EBR can alleviate the wilting and curling of leaves caused by salt-alkali stress, and the plant growth condition gradually improves.?At the same time, it effectively reduces the REC, MDA and Ci of seedling leaves, and significantly increases plant height, leaf area, Primary root length, Pro, SS, Pn, Tr and Gs as well as SOD, POD, CAT and APX activities, but these salt-alkali resistance effects of common beans induced by exogenous 2,4-EBR were reversed after adding BRZ.【Conclusion】 Exogenous 2,4-EBR treatment can reduce membrane lipid peroxidation damage caused by salt-alkali stress by increasing antioxidant system enzyme activity and osmotic adjustment substance content in common bean leaves. It effectively removes the non-stomatal limiting factors that weaken the photosynthesis of common bean seedlings under saline-alkali stress, maintains the photosynthetic activity of the seedlings, promotes seedling growth, and enhances the salt-alkali resistance of common bean seedlings.

Cloning and Disease Resistance Function Analysis of the Potato Phytosulfokine Gene StPSK4

WANG Xiang, NIU Yang, XUE Xiaofei, CHENG Shengyang, LU Haibin

2024,44(8):1218-1228, DOI: 10.7606/j.issn.1000-4025.20240237

[Abstract] (123) [HTML] (0) [PDF 7.13 M] (20275)

Abstract:
【Objective】 The study aims to provide a theoretical basis for potato disease resistance breeding by investigating the characteristics of the potato defensin gene StPSK4 and conducting a functional analysis of its role in potato disease resistance. 【Methods】 The authors Utilized bioinformatics techniques for a systematic analysis of StPSK4, conducting transcriptome sequencing analysis to study the tissue-specific expression patterns of StPSK4 under biotic and abiotic stress conditions, assessing the plant innate immune responses and sensitivity to Pseudomonas syringae in StPSK4 overexpressing plants. 【Results】 The cDNA full length of the StPSK4 gene was 457 bp, encoding 100 amino acids; StPSK4 contains a signal peptide, with its tertiary structure mainly composed of α-helices and random coils; The C-terminus of PSK4 contains the defensin sequence YIYTQ; StPSK4 shared a high similarity of over 80% with Solanaceae crops; StPSK4 was highly expressed in potato sprouts and petioles, and showed strong responses to abiotic stresses such as high temperature, salt, P. syringae, and Phytophthora infestans. Transgenic potato plants overexpressing StPSK4 had been constructed and obtained. Overexpression of StPSK4 suppressed ROS burst in potato, defensed marker gene expression, and enhanced resistance to P. syringae. 【Conclusion】 StPSK4 was involved in potato stress response and suppressed potato's disease resistance function.

Cloning, Expression, and Function analysis of MADS-box Transcription Factor CaRIN Gene from Capsicum annuum

DUAN Minjie, YANG Xiaomiao, LI Yifei, HUANG Renzhong, HUANG Qizhong, ZHANG Shicai

2024,44(8):1239-1249, DOI: 10.7606/j.issn.1000-4025.20240111

[Abstract] (148) [HTML] (0) [PDF 3.98 M] (20233)

Abstract:
【Objective】 The study aims to explore the expression characteristics and function of RIN gene of MADS-box, and analyze its impact on the metabolism of carotenoids in pepper. 【Methods】 Based on the transcriptome of pepper fruit development, the full-length CDS of MADS-box transcription factor CaRIN gene related to chili ripening was cloned. Then the bioinformatics, expression patterns, subcellular localization, and transcriptional activation activity were conducted, and the effects of VIGS-induced CaRIN gene silencing on carotenoid metabolism were investigated. 【Results】 (1) The CDS region of CaRIN gene was 732 bp in length. The CaRIN gene encoded a protein containing 243 amino acids with a protein molecular weight of 27.95 kD and an isoelectric point (pI) of 7.06. The CaRIN protein has typical MEF2_ Like MADS domain, belonging to the MICK type transcription factor. (2) CaRIN gene is mainly expressed in flowers and fruits with tissue specificity. CaRIN was located in the nucleus and had transcriptional activation activity. (3) The promoter of CaRIN gene had several hormone response elements such as ABRE, and exogenous ABA and ethephon could accelerate the red turning of fruit and induce the high expression of CaRIN and related genes. (4) After VIGS-induced gene silencing of CaRIN, the expression levels of PSY1, CCS, PDS, CRTZ, LCYB and NCED1 of the carotenoid metabolic pathway genes were decreased by 0.27-0.59 times and the total carotenoid content in fruits (0.379 mg/g) was also significantly decreased compared with the control group (0.650 mg/g). 【Conclusion】 CaRIN may be an important regulatory factor of carotenoid metabolism in capsicum fruit.

Anatomical Study of Nectar Gland Development and Changes in Sugar Content in Caucasian Clover (Trifolium ambiguum Bieb. )

TI Zhonghui, WANG Mingjiu

2024,44(8):1305-1311, DOI: 10.7606/j.issn.1000-4025.20230847

[Abstract] (116) [HTML] (0) [PDF 3.00 M] (20225)

Abstract:
【Objective】Caucasian clover (Trifolium ambiguum Bieb.) is an excellent nectar source plant, and understanding the morphological characteristics, tissue structure, and development was critical for its reasonable utilization.【Methods】Well-grown standard plants of Caucasian clover were selected and sampled at different developmental periods of the florets, i.e., flower bud visible, petal visible, floret with white petal, floret with pink petal, and floret withered. The paraffin sectioning technology was used to observe the cell and tissue structure of the florets. The starch and soluble sugars including sucrose, fructose, and glucose were determined by capillary aspiration and physiological kit and spectrophotometry at the flower bud visible, petal visible, floret with white petal, floret with pink petal, and floret withered. 【Results】The results showed that: (1) The nectar amount of a individual floret was 0.394±0.095 μL, and the nectar amount per meter square was 4536.93±1319.34 μL. (2) The stamens nectar gland was located at the base of the inner filament of the 9-stamen-combined. The nectar gland tissue had obvious dynamic changes in the starch granules during the whole honey secretion process after PAS staining, which evidenced it was the amyloid nectar gland. (3) The soluble sugar content of floret was the highest at floret with pink petal stage with 7.978 mg/g. Fructose accounted for the largest proportion among the soluble sugar category, peaked at the floret with white petal stage with 66%, decreased gradually after this stage. The starch content accounted for 81%~82% of the total soluble sugar content with a maximum value of 35.173 mg/g at the floret with pink petal stage and the minimum value of 24.168 mg/g at floret with white petal stage. 【Conclusion】The nectar glands of the Caucasus clover belong to the stamens nectar glands, which are composed of secretory epidermal cells and nectar cells. The raw honey is provided by the vascular bundles adjacent to the nectar glands, processed into honey by the nectar gland cells, and finally secreted from the stomata of the epidermis. The soluble sugar content of Caucasus clover florets was the highest in the full flowering stage, and the proportion of fructose was the largest.

A preliminary study on the expression analysis of the BcCHC1 gene in non-heading Chinese cabbage

LIU Fang, LU Shanwu, YUAN Mengguo, YANG Zirui, HOU Xilin, ZHANG Changwei

2024,44(8):1229-1238, DOI: 10.7606/j.issn.1000-4025.20230439

[Abstract] (85) [HTML] (0) [PDF 19.69 M] (20212)

Abstract:
【Objective】 In order to improve TuMV resistance of non-forming Chinese cabbage, the interaction mechanism between BcCHC1 gene and TuMV was investigated. 【Methods】 In this study, a member of the clathrin heavy chain CHC gene family was identified from cabbage and a CHC1 was cloned, and subcellular localization of the CHC1 was performed. CI and 6K2 were screened from the candidate genes by bicolecular fluorescence complementary detection. VIGS induced BcCHC1 silencing and the plants died. BiFC test confirmed the interaction between BcCHC1 and TuMV proteins. 【Results】 The results showed that: (1) BcCHC1 gene was cloned successfully, and its coding sequence length was 5 124 bp, encoding 1 708 amino acids. (2) After 30 days of TuMV infection, the results of real-time fluorescence quantitative PCR showed that the relative expression of BcCHC1 in TuMV inoculated lines decreased significantly. (3) Subcellular localization found that BcCHC1 was located in the cell membrane and nucleus of tobacco epidermal cells. (4) The observation of BcCHC1 gene silenced lines showed that BcCHC1 silenced plants had died before TuMV inoculation. (5) Through BiFC experimental verification analysis, it was found that BcCHC1 could interact with CI and 6K2, and the interaction position with CI was mainly in the nucleus, while the interaction position with 6K2 was mainly in the cell membrane. 【Conclusion】 The study speculated that BcCHC1 interacts with TuMV''s CI and 6K2 to regulate TuMV infection of non-knotting Chinese cabbage by influencing clastrin-dependent endocytosis pathway and viral replication, etc. However, the specific mechanism of BcCHC1 regulating TuMV infection of non-knotting Chinese cabbage needs further study.

Diurnal variation characteristics of photosynthesis and chlorophyll fluorescence of six grape varieties at greenhouse in Hotan area

GUO Yawen, XUE Jing, SONG Guangyong, SU Xuede, YANG Keqing, ZHOU Long

2024,44(8):1208-1217, DOI: 10.7606/j.issn.1000-4025.20230735

[Abstract] (105) [HTML] (0) [PDF 860.15 K] (20197)

Abstract:
[Objective] The diurnal variation characteristics of photosynthesis and chlorophyll fluorescence of greenhouse grape varieties in Hotan area were discussed, and their photosynthetic capacity was comprehensively evaluated, so as to provide reference for the introduction and cultivation management measures of greenhouse grapes in this area. [Methods] Six grape varieties ‘Hutai 8’‘Queen Nina’‘Summer Black’‘Sunshine Muscat’‘Xinyu’ and ‘Crimson Seedless’ were introduced into Hotan greenhouse as experimental materials. The photosynthetic active radiation (PAR), relative chlorophyll content (SPAD), photosynthesis and chlorophyll fluorescence parameters of each variety were measured and analyzed, and the principal component analysis was used to comprehensively evaluate the ability of each table grape variety. [Results] (1) The photosynthetically active radiation of greenhouse in different positions in general shows that before the shed>behind the shed>middle the shed, and the overall performance in different trellis in general shows that on the trellis＞middle the trellis＞under the trellis. (2) The SPAD values of grape leaves on different trellis was shown as on the trellis＞middle the trellis＞under the trellis, and the order from high to low among varieties was ‘Crimson Seedless’‘Summer Black’‘Xinyu’‘Hutai 8’‘Sunshine Muscat’‘Queen Nina’.(3) The diurnal variation of Pn、Gs and Tr of each variety showed a bimodal curve, and the diurnal variation of Ci showed a U-shaped and W-shaped variation.Fv/Fo and Fv/Fm generally showed a downward trend and then an upward trend. (4) The photosynthetic capacity of six grape varieties was ‘Crimson Seedless’>‘Summer Black’ >‘Sunshine Muscat’ >‘Xinyu’>‘Hutai 8’>‘Queen Nina’. [Conclusion] ‘Crimson Seedless’ and ‘Summer Black’ have higher Pn、Gs、Tr、Fo、Fm and lower Fv/Fo and Fv/Fm compared to other varieties, and are better adapted to the Hotan area, able to adapt to the local environment of high temperature and highlight intensity facilities.

Effect of bagging and shading on the contents of sugar acid and flavonoids in Cerasus humilis

YANG Yu, YAN Songtao, FU Hongbo, WANG Pengfei, DU Junjie, MU Xiaopeng

2024,44(8):1201-1207, DOI: 10.7606/j.issn.1000-4025.20230757

[Abstract] (137) [HTML] (0) [PDF 563.06 K] (20191)

Abstract:
【Objective】 To investigate the effects of different light exposure durations and intensities on the sugar, acid, and flavonoid contents of Cerasus humilis fruits, and to provide a reference basis for further exploration of the molecular mechanisms underlying the influence of light exposure on fruit quality. 【Methods】 The C. humilis varieties ''Nongda 6'' and ''Nongda 7'' were used as experimental materials. Fruit bags with three different light transmission rates (30%, 55%, and 100%) were respectively applied during the fruit enlargement period and color conversion period to measure the fruit weight, titratable acid content, soluble solids content, and flavonoid content. 【Results】(1) The single fruit weight and soluble solids content of both varieties were lower during the fruit enlargement period than during the color conversion period, and both decreased gradually with increasing light-blocking rate of the fruit bags. (2) The titratable acid content of ''Nongda 6'' was significantly reduced under bagging treatment, and the higher the light blocking rate of the fruit bag and the longer the bagging time, the more pronounced the reduction in acidity. In contrast, the titratable acid content of ''Nongda 7'' was less affected. (3) The flavonoid content of bagged ''Nongda 6'' was higher than the control, increasing first and then decreasing with the increase in light-blocking rate of the fruit bag, and the content during the fruit enlargement period was higher than that during the color conversion period. The flavonoid content of bagged ''Nongda 7'' was significantly higher than the control only at a 30% light-blocking rate, and the content during the fruit enlargement period was significantly lower than that during the color conversion period. The content increased gradually with the increase in light-blocking rate during the fruit enlargement period, while it first decreased and then increased during the color conversion period. 【Conclusion】 Bagging can effectively improve the sugar, acid, and flavonoid contents of C. humilis fruits. Furthermore, bagging during the fruit enlargement period is suitable for ''Nongda 6'', while bagging during the color conversion period is more effective for ''Nongda 7''. Both varieties show the best overall improvement in sugar, acid, and flavonoid contents with a 55% light-blocking rate on the fruit bag.

Comparison of the Leaf Epidermal Micromorphology between Female and Male Idesia polycarpa Maxim.

YIN Dandan, SU Shang

2024,44(8):1312-1320, DOI: 10.7606/j.issn.1000-4025.20240070

[Abstract] (94) [HTML] (0) [PDF 2.58 M] (20170)

Abstract:
【Objective】The study aimed to explore the micromorphological characteristics of leaf epidermis of Idesia polycarpa Maxim. and compare differences between the female and male plants, and provide references for the mining and utilization of this germplasm resources. 【Methods】The leaf epidermal micro-configurations of 40 plants of I. polycarpa (half female and half male) were characterized with scanning electron microscopy. Meanwhile, 12 stomatal traits were measured, and the similarities and differences among samples were analyzed. 【Results】(1) The leaf epidermal hair, cell morphology, stomatal characteristics and wax pattern of both female and male I. polycarpa were similar. Its dense, conical conicoid-like wax covered on the abaxial epidermis was rarely observed in other plants. (2) The leaf stomatal size (length, width, area and perimeter) and density related parameters of female I. polycarpa were slightly higher than those of male samples. On the contrary, leaf stomatal pore related parameters (stomatal pore width, stomatal opening area and stomatal opening level) were slightly higher in male samples. But all differences were not statistically significant (P > 0.05). (3) Most stomatal traits were significantly correlated with each other, while stomatal density was rarely related with others and was supposed to be genetically regulated independently. 【Conclusion】The present study firstly expounded the leaf epidermal micromorphological characteristics of I. polycarpa, and indicated that the conical conicoid-like wax pattern could be used as a key basis for germplasm evaluation, and the stomatal parameters were of great significance for gender determination of its young seedlings.

Characterization of repetitive sequences in Leymus secalinus and chromosomal distribution in related species

CHEN Jie, LI Yuan, YANG Ying, LIU Bo, DOU Quanwen

2024,44(8):1273-1282, DOI: 10.7606/j.issn.1000-4025.20230751

[Abstract] (120) [HTML] (0) [PDF 4.36 M] (20161)

Abstract:
[Objective] Leymus Hochst stands as a crucial genetic resource for the genetic improvement and breeding of cereal crops. However, as allopolyploids, their genome origin remains unclear. [Methods] Genomic Cot-1DNA library of Leymus secalinu was constructed, clones of which were sequenced and analyzed. A few of repetitive sequences were physically mapped in chromosomes of L. secalinus, L. racemousus, and Psathyrostachy juncea by Fluorescence in situ hybridization (FISH). [Results] (1)The repetitive sequences of the Cot-1DNA of L. secalinus could be classified into 4 types based on their expected genomic distribution patterns, tandem repeats (TaiI, Lt1-6, pTa535 and pSc250 family), dispersed repeats (retrotransposable LTR and transposable elements), tandem mixed dispersed repeats (LTR plus Afa-family and N8-family plus LZ-NBS-LRR), and uncharacterized repeats, and which represented 32.4%, 45.7%, 12.4% and 9.5% of the Cot-1DNA, respectively. (2) The hybridization sites number of tandem repeats TaiI, Lt1-6, pTa535 and pSc250 were highly varied from 7-20, 1-14, 17-26 and 0-24 respectively, across different species and accessions. (3) Ten LTR repeats hybridized the tested species chromosomes mainly by 3 patterns: First, hybridizations distributed in centromere, pericentromere, and intercalary regions in all chromosomes. Second, hybridizations were all over the chromosomes. Third, Hybridizations were as the same as the pattern 1 except a few chromosomes carrying telomeric hybridizations. Two LTR/copia sequences were detected only in L. secalinus, while the others were detected in all tested species and accessions but with polymorphisms in hybridization intensities or hybridization patterns in partial chromosomes. [Conclusion] The results suggested rather fast-evolving repetitive sequences in Leymus genome, and supported hypothesis that the dispersed elements must have spread across genomes, thus homogenizing the nuclear genomes of Leymus during the allopolyploidization process.

Identification of CPP Gene Family and Analysis of ExogenousSelenium Response in Foxtail Millet

YANG Furong, DU Bing, GUO Haojie, Wang Cheng, ZHANG Fuhou, MENG Chaomin

2024,44(8):1250-1260, DOI: 10.7606/j.issn.1000-4025.20240163

[Abstract] (90) [HTML] (0) [PDF 2.09 M] (20159)

Abstract:
【Objective】To explore the basic characteristics of CPP family members of foxtail millet and their response mode under exogenous selenium treatment, and to provide new genetic materials for the breeding of innovative varieties rich in selenium and high folate in foxtail millet. 【Methods】Using bioinformation tools to identify CPP family members, using qRT-PCR technology to determine CPP gene expression in various organizations and in exogenous selenium, which laid a foundation for revealing the biological function of CPP family and the response mechanism of exogenous selenium in foxtail millet. 【Results】(1) The millet genome contained 9 CPP genes, which were located on 6 chromosomes and were named SiCPP1-SiCPP9 according to the arrangement of genes in chromosomes. Amino acids ranged from 220 to 899, the relative molecular weight ranged from 23624.32 to 97253.16Da, and the isoelectric point ranged from 6.64 to 9.17, the number of introns ranged from 3 to 11, subcellular predictions showed that all family members could position themselves in nucleus. The prediction of the secondary structure of the protein indicated that the proportion of irregular curling and α-helix in the family was the heaviest.. (2) Phylogenetic analysis showed that gluten proteins could be divided into four subfamilies, the number and distribution of conservative elements and structural fields among the same subclans. (3) Promoter analysis revealed a large number of light, growth and development, hormone and stress response elements in foxtail millet CPP family. (4) Fluorescence quantitative results showed that CPP family members were differentially expressed in root, stem, leaf and ear.All 9 members of the millet CPP family were responsive to exogenous selenium, among which SiCPP5, SiCPP6, SiCPP7 and SiCPP8 were the most responsive. 【Conclusion】Members of the millet CPP family had tissue expression specificity and varying degrees of response to exogenous selenium.

QTL mapping and Candidate Gene Identify of Seed Glucosinolate Content in Brassica napus

ZHAO Weiguo, TA Na, WANG Hao

2024,44(8):1261-1272, DOI: 10.7606/j.issn.1000-4025.20240120

[Abstract] (70) [HTML] (0) [PDF 984.20 K] (20147)

Abstract:
【Objective】To explore the genetic loci and candidate genes of glucosinolate content in Brassica napus, 【Methods】 The phenotype data for glucosinolate content of a double haploid (DH) population named KN population was surveyed in the year 2013-2017 for QTL mapping and identification of candidate genes using composite interval mapping by Wincart 2.5 software based on the high-density SNP genetic linkage map. 【Results】A total of 47 identified QTLs for glucosinolate content were detected, individual QTLs could explain 2.48%–19.63% of the phenotypic variation, of which qGC.16YL19-4 was the maximum phenotypic variation of 19.44% and qGC.15YL12-5 was the minimum phenotypic variation of 1.82%. 47 identified QTLs were integrated into 38 consensus QTL by meta-analysis. Seven environment stable expression QTLs (cqGC.A9-5, cqGC.A9-7, cqGC.A9-9, cqGC.C2-9, cqGC.C2-10, cqGC.C9-5 and cqGC.C9-6) for glucosinolate content were identified, including three major QTLs (cqGC.A9-5, cqGC.C2-10 and cqGC.C9-5). Three candidate genes (BnaA09g05480D, BnaC09g05620D and BnaC09g05810D) within major QTL confidence interval were identified, which were located in two major QTL regions. Based on their annotation, these candidate genes involved in the biosynthetic pathway of glucosinolates (the biosynthesis of IAOx and isomerization of 2-alkyl malic acid to form 3-alkyl malic acid ester) and transport and distribution of glucosinolates. 【Conclusion】 Three major QTLs for glucosinolate content and three candidate genes were identified, these results lay the provide theoretical basis for functional analysis of genes and the cultivation of fine quality rapeseed varieties in the future.

Allelopathic effects of leaf extracts from economic forests on the growth of Fabaceae and Poaceae pasture grasses

HE Bangyin, HU Jiajia, PEI Jinghong, FANG Meiyan, LI Jiangwen

2024,44(8):1295-1304, DOI: 10.7606/j.issn.1000-4025.20240059

[Abstract] (100) [HTML] (0) [PDF 1.18 M] (20141)

Abstract:
Abstract 【Objective】 Allelopathy is one of the main factors affecting understory grass growth, and the chemosensitivity effects of fading leaves of Ziziphus jujuba, Juglans regia and Malus pumila in northern Shaanxi are not yet clear. 【Methods】 Outdoor Medicago sativa and Lolium perenne potting experiments were carried out by setting up different concentrations of Z. jujuba, J. regia and M. pumila withered leaf extracts (concentrations of 0.1, 0.05, 0.025 and 0.0125 g/mL).【Results】 (1) The biomass of both forages was significantly reduced under the J. regia and M. pumila leachate treatments, with L. perenne having only 0.45 g fresh weight per plant, Compared to the control group, the M. sativa only had 4.70 g. Plant height first increased and then decreased with increasing concentration of the leaching solution (P < 0.05). (2) The content of malondialdehyde in M. sativa and L. perenne treated with different extracts was higher than that in the control group. The biochemical indicators of the two grasses showed significant differences in different types of extracts (P < 0.05). (3) J. regia and M. pumila extracts showed significant differences in root traits of M. sativa and L. perenne (P < 0.05). 【Conclusion】 The biomass of M. sativa and L. perenne respond differently to different extracts, exhibiting an "increase or decrease" effect, The treatment of Z. jujuba extract is more suitable for the growth of L. perenne, and the interaction between M. sativa and L. perenne, and economic forests should be fully considered.

Morphology and Histochemistry of the Glandular Trichomes of Isodon rubescens (Hemsley) H. Hara [Lamiaceae]

刘孟奇

2011,31(11):45-50, DOI:

[Abstract] (7426) [HTML] (0) [PDF 0.00 Byte] (18025)

Abstract:
The morphology and distribution of leaf trichomes of Isodon rubescens were studied using light microscopy. Three morphologically distinct types of trichomes were observed on I. rubescens leaf surfaces: non-glandular, peltate and capitate glandular. The glandular and non-glandular trichomes were present on both the adaxial and abaxial surfaces. Peltate and capitate glandular trichomes comprised one basal cell, one or two stalk cells and one head. The head of mature peltate glandular trichomes generally consisted of four secretory cells while that of capitate glandular hairs was composed of two cells. Histochemical results indicate existence of flavnoids in both peltate and capitate glandular trichomes. In addition, terpenoids, including monoterpenes, sesquiterpenes etc., exist in peltate glandular trichomes. Peltate glandular trichomes are probably only site of oridonin accumulation, however, this need direct proof to clarify. High density of peltate trichomes might be considered as an important selection character for the screening of I. rubescens with rich content of oridonin．

Preliminary Study on the Phylogenetic Relationship of Rosa rugosa ‘Hetian shamomeigui’

SUN Meile¹, ZHANG Jun¹, LI Yan², LIN Guocang^1*

2021,41(2):222-233, DOI: 10.7606/j.issn.1000-4025.2021.02.0222

[Abstract] (1793) [HTML] (0) [PDF 14.05 M] (15811)

Abstract:
In this study, we studied the relationship between Hetian rose variety (Rosa rugosa ‘Hetian shamomeigui’) and Zizhi rose (R. rugosa ‘Zizhi’), Fenghua rose (R. rugosa ‘Fenghua’) and Damask rose (R. damascena) with molecular data, investigated the phylogenetic relationship of the Hetian rose within genus Rosa, and discussed its hybridization origin. Results showed that: (1) the Hetian rose had unique genetic source. The genetic distance within the Hetian rose (0.017±0.003) was smaller than the distance between varieties (0.029±0.005, 0.024±0.004, and 0.022±0.003, respectively). (2) The phylogenetic tree showed that GAPDH gene clones of the Hetian rose did not mix with the gene clones from other varieties. These indicated that the Hetian rose was genetically diverged from the other three roses, and should be regarded as an unique rose variety. (3) A part of GAPDH clones of the Hetian rose were clustered with four species (R. bracteata, R. laevigata, R. cymosa, and R. banksiae) in Rosa sect. Bracteatae, sect Laevigatae, and sect. Banksiae from China or Southeast Asia, located at basal position of the phylogenetic tree, while other GAPDH clones were clustered with other four European species (R. elliptica, R. sempervirens, R. trachyphylla, and R. abyssinica) in sects. Caninae, Synstylae, and Gallicanae. A total of 19 GAPDH heterozygous loci were detected between the Hetian rose and the above mentioned closely related species, indicating a hybrid origin of Hetian rose. (4) A close relationship between the Hetian rose and 14 European species from sect. Caninae, sect. Synstylae, and Gallicanae was revealed by cpDNA phylogeny and sequence variation analysis. In conclusion, it was proposed that the Hetian rose had a hybrid origin by Chinese and European rose species or varieties. The hybrid parents may be the one or more species in sects. Bracteatae, Laevigatae, Banksiae, Caninae, Synstylae, and Gallicanae. This study provides a foundation for further research on the probable parental species of the Hetian rose.

Biosynthesis Metabolic Pathway and Molecular Regulation of Plants Anthocyanin

JIA Zhaodong¹, 2, MA Peiyong¹, BIAN Xiaofeng¹, YANG Qing², GUO Xiaoding¹, XIE Yizhi^1*

2014,34(7):1496-1506, DOI: 10.7606/j.issn.1000-4025.2014.07.1496

[Abstract] (5560) [HTML] (0) [PDF 656.79 K] (14414)

Abstract:
Plant anthocyanin is a kind of natural edible pigment,has many advantages:safety,no pollution,outstanding stability;it showed noticeable antioxidant ability,which can prevent cancer and protect the function of the liver,prevention and protection of cardiovascular and cerebrovascular diseases,and other important nutritional and pharmacological function.Therefore,anthocyanin has important research value and potential applications in food,medicine and health care,horticulture and crop improvement.Here we review recent progresses in biological functions and mechanisms of structural genes and regulator genes in anthocyanin biosynthesis and metabolic pathway,including the anthocyanin biosynthetic,metabolic and accumulative process in plant.Prospective of application prospect and development tendency accumulative processon the anthocyanins genes are elucidated in the end.

Molecular Cloning and Expression Analysis of CjMYB1 in Camellia japonica

HUANG Hu¹, 2, MA Xianjin¹, 2, LI Sijia¹, LI Xinlei¹, LI Jiyuan¹, YIN Hengfu^1*

2022,42(3):381-389, DOI: 10.7606/j.issn.1000-4025.2022.03.0381

[Abstract] (1301) [HTML] (0) [PDF 11.92 M] (13270)

Abstract:
In this study, based on sequence alignment analysis, we cloned the full-length CjMYB1 gene from wild Camellia japonica and performed gene expression analyses in Camellia varieties with different floral colors, which provided a fundamental basis for understanding the function of CjMYB1 underlying the floral color formation during flower development. The results showed that: (1) CjMYB1 gene (GenBank accession: OL347930) was successfully cloned. Its open reading frame length was 879 bp, encoding a 292 amino acids protein with relative molecular weight of 33.17 kD. CjMYB1 is found to be a R2R3-MYB transcription factor and is homologous to the subgroup 7 of Arabidopsis thaliana MYB gene family. (2) Quantitative real-time PCR analysis showed that CjMYB1 gene had the highest expression level in the floral buds of wild C. japonica, and had a relatively high expression level in sepals, petals, stamens and carpels, suggesting that CjMYB1 plays an important role of regulating the floral development. The expression level of CjMYB1 gene was higher in red Camellia varieties, but lower in pink, light yellow and white Camellia varieties, suggesting that CjMYB1 gene may play a key role in the anthocyanin synthesis pathway. (3) Subcellular localization experiments showed that CjMYB1 protein was located in the nucleus.

Generation of Reactive Oxygen Species and Their Functions and Deleterious Effects in Plants

ZHANG Mengru, YANG Yumei, CHENG Yunxiu, ZHOU Tao, DUAN Xiaoyan, GONG Ming, ZOU Zhurong^*

2014,34(9):1916-1926, DOI: 10.7606/j.issn.1000-4025.2014.09.1916

[Abstract] (5549) [HTML] (0) [PDF 2.92 M] (8576)

Abstract:
Reactive oxygen species (ROS) are a group of free radicals,reactive molecules and ions that are derived from O₂.It is estimated that about 1% of plants-consumed O₂ is converted to ROS in various subcellular compartments such as chloroplast,mitochondria,and peroxisome.ROS are well recognized for playing a dual role as both deleterious and beneficial factors,depending on their concentration in plants.At low concentration ROS acts as second messenger in signaling cascades that mediate several responses in plant cells,whereas at high concentration it triggers oxidative damages to biomolecules and even cell death.Equilibrium between ROS production and scavenging is crucial for plants,and monitored by an efficient antioxidative system consisting of both nonenzymic and enzymic antioxidants.This review thoroughly introduced the current proceedings of studies on plant ROS mainly in terms of their types,production sites,roles in signaling and major damages to plant cells,aiming to provide an insight for improving plant resistance to environmental stress through genetic engineering.