Abstract:In this study, a full length cDNA of flavanone 3hydroxylase (F3H) was cloned from the leaf of Ampelopsis grossedentata using RACE technique, and named AgF3H (accession number JX087441). The full length cDNA was 1 323 bp, containing a 1 092 bp open reading frame (ORF) encoding a protein consisting of 363 amino acids， with 2 typical functional domains and 5 conserved motifs of dioxygenase superfamily. Sequence comparison and phylogenetic tree analysis showed that the amino acid sequence of AgF3H had considerable similarity with those of other species, and had the closest evolutionary relationship with the F3H protein of Vitis vinifera, Vitis amurensis and Vitis rotifera. Real time PCR showed that the expression level of AgF3H gene decreased gradually during the maturity of leaves. The highest expression level emerged in buds while the lowest expression level emerged in young stems. Correlation analysis revealed positive correlation between AgF3H gene expression and the content of dihydromyricetin, the main flavonoid component in A.grossedentata. After the overexpression vector of AgF3H gene was constructed and transferred to tobacco, five transgenic plants were obtained. Among them, the content of total flavonoids in leaves of four tobacco plants increased to different degrees compared with wild type control, and the highest line increased by 26.8%. The study indicated that AgF3H gene may play an important role in the biosynthesis of flavonoids in A. grossedentata and the results lay a foundation for further exploring the molecular mechanism of the formation of high flavonoids content in A. grossedentata.

Abstract:Phytoene desaturase (PDS) is the key enzyme in the biosynthesis pathway of carotenoids. In order to further explore the functions of PDS gene in Antirrhinum majus, the fulllength sequence and protein structure of AmPDS were analyzed, and the gene fragment of AmPDS was cloned. To investigate the expression profiles of AmPDS genes, the relative expression level of AmPDS gene in different periods and organs was detected by qRTPCR, the function of AmPDS gene was verified by VIGS, and the content of various pigments in leaves was determined by UV spectrophotometry. The results showed that： (1) the AmPDS gene forgment (500 bp) was cloned correctly, the cDNA of AmPDS gene was 1 743 bp in length, encoding 580 amino acids; Its protein molecular weight was 64.75 kD, and the the theoretical isoelectric point was 6.66. Homology analysis showed that the AmPDS gene has the highest sequence similarity to the sesame (Sesamum indicum). (2) qRTPCR analysis showed that the AmPDS gene was expressed in the whole plant, and the highest expression level was found in the upper lobes of the flower in fully opened period and leaves. (3) The pTRV₂AmPDS vector was successfully constructed and the VIGS system of snapdragon was established. The silencing efficiency of AmPDS gene was about 53% while the contents of various pigments in the leaves were significantly reduced comparing with the negative control. AmPDS is a key gene in the carotenoid biosynthesis pathway of snapdragon, and its obvious phenomenon can be used as an indicator gene for the VIGS system of snapdragon, which can lay a foundation for the further study of other gene functions of snapdragon.

Abstract:MYB transcription factor is one of the most representative transcription factor families in all eukaryotes. It is widely involved in plant development, phenylpropanoid metabolism, biotic and abiotic stress response, hormone response, and cell morphogenesis. In this study, StMYB44 gene (GenBank accession number is XM_006367359.2) was cloned from potato ‘Qingshu 9’, whose sequence length was 963 bp, encoded 320 amino acids that contained two SANT domains. The result of quantitative realtime PCR showed that StMYB44 had the highest expression in flowers and the lowest expression in stolon; StMYB44 was upregulated under sucrosefree treatment and downregulated under highconcentration sucrose treatment (6%, 9%). Construction of expression vector and genetic transformation of tobacco found that the growth of StMYB44 mutant under sucrosefree conditions was significantly better than that of wildtype, while at high sucrose concentration (6%, 9%), the growth of StMYB44 mutant was weaker than wildtype, and the higher the sucrose concentration, the difference is greater. These results indicates that sucrose concentration can regulate the expression of StMYB44, suggesting that this gene may play an important role in plant response to sucrose.

Abstract:BNS is an efficient thermophotosensitive genic male sterile line of wheat (Triticum aestivum). It is sterile in low temperature and fertile in high temperature. With these features, BNS was widely used in hybrid wheat breeding. In this study, based on the gene chip data of the anthers of BNS sterile line and fertile line, we found that the transcription factor TaERF7 was differentially expressed between the two lines, and cloned the cDNA and promoter sequences of TaERF7，analyzed TaERF7 response to temperature and day length by qRTPCR. The results showed that: (1) bioinformatics analysis revealed that the coding sequence (CDS) of TaERF7 is 660 bp and encoding of 219 amino acids. TaERF7 protein contains AP2 domain and two EAR motifs. It belongs to class Ⅱ ethylene response factors (ERFs). The amino acid sequence of TaERF7 is homologous to AtERF4 in Arabidopsis (Arabidopsis thaliana), which is a transcriptional repressor. The promoter region contains multiple cisacting elements with light and low temperature response. (2) The qRTPCR results showed that TaERF7 expressed in different tissues of BNS. The expression of TaERF7 was downregulated 0.47 fold under long daylight (14 h), while it was upregulated 1.14 fold under short day (10 h). The low temperature treatment at 4 ℃ increased the expression of TaERF7 about 25.7 fold in 2 h, and maintained a high level upto 48 h. The high temperature treatment at 37 ℃ increased the expression of TaERF7 about 0.71 fold in 1 h, but it was sharply downregulated to 0.85 fold after 2 h. According to the above results, we speculated that TaERF7 combined to cisacting element of downstream genes, regulated their expression, and caused the male sterility in BNS.

Abstract:As a family of transcription factors, WRKY protein plays an important regulatory role in plant growth and development and in response to environmental signals. In this study, the whole genome data of pomegranate were used to systematically analyze the proteins physicochemical properties, phylogenetic evolution, gene structure, conserved motifs, cisacting elements, protein interaction, gene coexpression, and transcriptome expression patterns of pomegranate WRKY transcription factors by bioinformatics. We identified 69 genes. PgWRKY gene group identification and evolutionary analysis show that WRKY proteins can be divided into Ⅰ, Ⅱ and Ⅲ altogether three types. Cisacting element analysis showed that PgWRKY gene was widely involved in abiotic stress. Protein interaction network and coexpression analysis suggested that PgWRKY gene might play a consistent role in the same stress response and induce expression simultaneously. RNAseq data analysis indicated that PgWRKY gene had certain tissue expression specificity and was widely involved in plant nutrition, reproductive growth and root stress response.

Abstract:In this study, the CsGME1 gene was cloned from cDNA of Camellia sinensis cv. ‘Longjing43’ based on the transcriptome and genome database of tea plant. Its protein characteristics and gene expression patterns were analyzed. In addition, the expression profiles of the CsGME1 under abiotic stress treatments in tea plant were detected by quantitative real time PCR. The main results listed below: (1) sequence analysis showed that the length of CsGME1 open reading frame (ORF) of tea plant was 1131 bp, encoding 376 amino acids. Multiple alignments of CsGME1 with related species showed that the identity of them was 94.25%, and all contain NAD binding domain. (2) Analysis of phylogenetic tree indicated that the CsGME1 was closely related to SlGME1 from Solanum lycopersicum, but far from OsGME2 of Oryza sativa. (3) Protein analysis suggested that the CsGME1 is a hydrophilic protein with the theoretical relative molecular weight 42 046.84 Da and the theoretical isoelectric point 5.73. CsGME1 protein had 4 disordered regions with low degree of disorder. Secondary structure prediction showed that the CsGME1 protein consists of 39.25% αhelix, 13.26% extended strand, 5.84% βturn and 41.38% random coil. The threedimensional structures indicated that CsGME1 protein contains helix and random coil. (4) The results of quantitative real time PCR showed that the CsGME1 gene responded to four kinds of abiotic stress treatments: high temperature (38 ℃), low temperature (4 ℃), drought (20% PEG) and high salinity (200 mmol·m^-1 NaCl). The expression profiles showed difference.

Abstract:In this study, the test material was carried out using RILs (recombinant inbred lines) derived from the cross of ‘Shannong 0431 × Lumai 21’. Drought and salt environments were simulated with 20% PEG6000 solution and 100 mmol·L^-1 NaCl, respectively. We analyzed quantitative trait loci (QTL) for drought and salt tolerant related traits in wheat on the 12 drought and salt tolerant traits in wheat germination, combining with a genetic map constructed by our group, to provide references for the cloning of salttolerant and droughtresistant genes and markerassisted selection of wheat. The results showed that: (1) a total of 143 QTLs were detected for 12 traits under normal, drought and salt environments. A number of 29 RHFQTLs were detected with the average contribution rate ranged from 4.39% to 13.28%. Among them, the contribution rate of 10 RHFQTLs was more than 10%. (2) A total of 17 and 8 RHFQTLs with specific expression were detected under stress and normal treatments, respectively. Four RHFQTLs with stable expression were detected. (3) A number of three QTL clusters formed by 7 RHFQTLs were detected, distributing on chromosomes 2D, 4D and 5B. Among them, QC1 was located in the wPt6847-D1172783 of 2D chromosome, including three QTLs (QRl2D.2， QSdw2D.3， QTdw2D). QC2 was located in the D2245724-D1108531 of 4D chromosome, including two QTLS (QSl4D, QShl4D). QC3 is located in D982263-S1083095 of chromosome 5B chromosome, including two QTLS (QSl5B.2， QTdw5B.1).

Abstract:Two regeneration systems were established by using sterile leaves of wild Lycium ruthenicum. The direct organogenesis is differentiated by leaves, and the indirect organogenesis is differentiated by calli. The genetic stability of the regenerated plantlets was assessed by the ISSR markers and flow cytometry(FCM). The results showed that: (1) the best medium for callus induction was MS+1.5 mg·L^-1 2,4D, with induction rate of 100%; the optimum medium for callus differentiation was MS+1.5 mg·L^-1 6BA+0.1 mg·L^-1 IBA, with 39.4 shoots per gram of calli. (2) The suitable medium for direct shoot induction was MS+0.5 mg·L^-1 6BA+0.3 mg·L^-1 NAA, with induction rate of 92.9%, and 18.1 shoots per explant. (3) After adventitious buds were transferred to the MS medium without hormones, the roots could form within two weeks. (4) FCM results showed that parental plantlets and regenerated plantlets were diploid. (5)ISSR analysis showed that the average genetic similarity coefficients of indirect and direct regenerated plantlets were 0.84 and 0.91. The direct organogenesis was a more effective method for plant regeneration of L. ruthenicum.

Abstract:In order to explore the influence of habitat on the micromorphology of Selaginella plants, we used a scanning electron microscope to comprehensively observe the morphological characteristics of lateral leaves, middle leaves, fertile leaves and microspores of seven Selaginella species collected in Qixianling, Hainan, and measured and calculated stomatal size, stomatal density, spore size. Differences in micromorphology and the relationship between micromorphology and habitat were compared and analyzed to provide a reliable basis for the classification of Selaginella species. Results show that: (1) lateral leaves, middle leaves and fertile leaves of the same species of Selaginella have obvious differences in leaf epidermal morphology, especially the stomata on fertile leaves are smaller and sparer than those of sterile leaves, which is consistent to the reproductive function of fertile leaves. (2) The leaf epidermis characteristics of different species of Selaginella are also distinct, mainly in leaf margin thorns, stomata and tumorlike bulges, indicating that these characteristics can be used as the basis for the distinction between species of Selaginella. (3) The microspores of Selaginella are stable in morphology and diverse in texture; the microspores in some species are similar in shape, but are distinguished by the type of ornamentation and the curvature of cracks. (4) The microspores of S. hainanensis have a unique mesh pattern, suggesting that it has a unique evolutionary pathway. (5) The stomata characteristics and the knoblike bulging characteristics of the leaf epidermis of Selaginella, the color and the ornamentation of microspores are related to the elevation and the moisture of habitat, but the mechanism needs further study.

Abstract:With the fluorescent lamp (16 mm diameter, 28W, light intensity 9.45 μmol·m^-2·s^-1) as light source to set up four supplementary treatments, including dark (T₀，without lamp) and low (T₁，one lamp), medium (T₂，two lamp) and high (T₃，three lamp) light intensities (8 h·d^-1), we simulated a onemonth of storage of Bougainvillea spectabilis ‘Crimsonlake’, and measured the defoliation rate, photosynthetic pigment content, cell membrane permeability, antioxidant enzyme activity and other related physiological and biochemical indexes of leaves, so as to study the effect of supplementary treatments on the leaves of B. spectabilis and provide the basis for solving the serious defoliation problem during storage and transportation of B. spectabilis. The results showed that: (1) on the 28th day of simulated storage, the defoliation rates of T₀ and T₃ treatments were serious, reaching over 87%, and the defoliation rates of T₁ and T₂ treatments were significantly lower than that of T₀ and T₃ treatments, only 16.33% and 16.92%; The specific leaf weight of T₁~T₃ treatments is higher than that of T₀ treatments, and the relative water content is lower than that of T₀ treatments. (2) The relative conductivity, MDA content, soluble protein content of T₁ and T₂ treatments were significantly lower than that of T₀ treatment. (3) The contents of chlorophyll a, chlorophyll b, total chlorophyll and carotenoid in leaves of T₀, T₂ and T₃ treatments increased firstly and then decreased, while that of T₁ treatment showed an upward trend with small changes. (4) During the whole storage and transportation period, the activity of superoxide dismutase (SOD) in the leaves showed a gradual increase, while the activities of catalase (CAT) and peroxidase (POD) increased firstly and then decreased. There was no significant difference in the CAT activity of leaves between T₀, T₁ and T₂ treatments. POD activity of leaves treated with T₁ and T₂ was significantly higher than that of T₀ treatment. On the 28th day, the SOD activity in the leaves of T₂ treatment was significantly higher than that of T₁ treatment, which increased by 60.86% and 45.02%, respectively, compared with the 0th day. The research indicated that the light intensity of 9.45 μmol·m^-2·s^-1, i.e. a fluorescent lamp, could be used to compensate light for 8 h·d^-1 on the B. spectabilis during storage, which could reduce damages of the cell membrane and influences of the photosynthetic pigment caused by the dark stress in the process of storage. It was beneficial to reduce the wastage of photosynthetic product in the leaves and the yellowing of the leaves, so that the B. spectabilis could grow normally during storage to reduce economic losses.

Abstract:By comparing the differences in tissue anatomy, membrane permeability, and endogenous hormones of different varieties of jujube kiwifruit during the natural wintering period, we investigated the adaptability of kiwifruit to low temperature in order to provide a theoretical reference for the selection and identification of coldresistant kiwifruit varieties.The fiveyearold kiwifruit cultivars ‘Kuilv’, ‘Fenglv’ and ‘966’ were used to determine the changes in anatomical structure of shoot tissue, cell membrane permeability and endogenous hormones such as GA₃, ABA, and IAA during the winter. We hope to determine the lowtemperature adaptability and its underlying mechanism of different varieties of kiwifruit. The result shows: (1) the xylem ratio from big to small is: ‘Kuilv’, ‘966’and ‘Fenglv’, and the cortex ratio is ‘Fenglv’, ‘966’and ‘Kuilv’. The anatomy of ‘Kuilv’ is significantly different from the other two varieties. (2) The relative electrical conductivity and MDA content of kiwifruit showed a trend that firstly increased and then decreased when temperature changes, and reached the highest in January that the temperature was the lowest. Among them, ‘Kuilv’ has the smallest change, and ‘Fenglv’ is affected by low temperature. (3) As the temperature dropped, GA₃ and IAA content gradually decreased, and ABA content gradually increased from November to January. With the change of natural temperature from November to February, the contents of GA₃ and IAA both decreased firstly and then increased, reaching the lowest value in January, and the ABA content increased firstly and then decreased, reaching a peak in January. Low temperature has a significant impact on the tissue anatomy, membrane permeability and endogenous hormones of three A. arguta varieties. Variety ‘Kuilv’ has the largest ratio of xylem and smallest ratio of cortex, and the smallest change in relative conductivity and MDA content.The endogenous hormone content GA₃ and ABA/GA₃ have a smaller change trend, so their cold resistance is stronger than that of ‘Fenglv’ and ‘966’.

Abstract:In this study, we used Populus tomentosa saplings as experimental material to analyze the leaf growth, photosynthesis and boron transporter (BOR) genes in response to shortterm excessive boron stress (1, 5, 10 mmol/L boric acid). The results showed that: (1) compared with the control (0.05 mmol/L boric acid, CK), 1 mmol/L boric acid treatment (BS₁) could lead to upregulation of chlorophyll fluorescence parameters and increase of reactive oxygen species in leaves, and a small amount of black necrotic spots appeared in the leaves at the base of the saplings. Under 5 mmol/L boric acid stress, the net photosynthetic rate, stomatal conductance and transpiration rate decreased, while intercellular CO₂ concentration increased. Chlorophyll fluorescence parameters and hydrogen peroxide content increased further, while ultraoxygen anion content was lower than BS₁, but still higher than CK. Necrotic spots showed up on most of the leaves. Under 10 mmol/L boric acid stress, gas exchange parameters, chlorophyll fluorescence parameters and reactive oxygen species content were similar to that of BS₅. All leaves showed necrotic spots with banded distribution that parallel to secondary veins. (2) The boron content in roots and stems changed slightly compared with CK, while in leaves it increased significantly under 5 mmol/L and 10 mmol/L boric acid stress. Boron translocation factor and bioconcentration factor maintained at a high level. (3) Several members of BOR gene family showed responses. In roots, following the increase of boron treatment concentration, the expression level of PtoBOR4 and PtoBOR8 increased firstly and then decreased. In stems, PtoBOR3 was downregulated while PtoBOR5 was upregulated. In leaves, PtoBOR7 and PtoBOR8 was upregulated. The present study showed that P. tomentosa leaves are sensitive to high boron stress in terms of chlorophyll fluorescence parameters, gas exchange parameters, reactive oxygen species, and the expression patterns of BOR genes, probably due to the strong ability to control the boron concentration in roots and the ability to transport boron rapidly from roots to aerial parts.

Abstract:In order to evaluate the effects of nanoselenium on growth, mineral element contents and quality characteristics of purple potatoes, in this study we treated the purple potato cultivar ‘black beauty’ under hydroponic cultivation with foliarspraying of different concentrations of nanoselenium (0, 0.38, 0.19 and 0.095 mmol/L). The results showed that: (1) biomass and tuber number per plant of all selenium treatments increased significantly compared with the control group, among which the highest increase of plant biomass under the treatment of spraying with 0.095 mmol/L selenium reached 1.5 times, and the tuber number per plant treated with spraying with 0.19 mmol/L selenium significantly increased by 2.2 times. (2) Nanoselenium could significantly improve the selenium content of leaves, roots and tubers of purple potatoes. The pattern of total Se concentration in different tissues of the plant followed the order of root>leaf>tuber, and the total selenium content in tubers reached 0.106 mg/kg under the treatment of spraying with 0.095 mmol/L selenium, which was significantly increased by 0.65 times compared with the control group, that is to meet seriched standard of potato tubers. Meanwhile, the distribution of K, Ca, Mg, Mn and Zn in potato tissues can be controlled by nanoselenium to different levels. (3) With the increase of selenium concentration in foliarspraying, the contents of starch, soluble protein and free amino acid in purple potato tubers were appeared the trend of unimodal trend, which reached the maximum value under 0.19 mmol/L selenium treatment, and increased significantly by 56.33%, 26.91% and 27.89% respectively compared with the control. Meanwhile, the contents of anthocyanin and soluble sugar in tubers showed a decreasing trend, which reached the maximum value under the treatment of spraying with 0.095 mmol/L selenium, and increased significantly by 24.73% and 25.33% respectively compared with the control; while the nitrate nitrogen content was on the rise, and decreased significantly by 34.82% compared with the control, which reached the minimum value under 0.095 mmol/L selenium treatment. Therefore, nanoselenium foliarspraying concentration at 0.095-0.19 mmol/L could significantly promote the growth and increase selenium content and quality characteristics of purple potato.

Abstract:In order to explore the variation law of rejuvenation based on tissue culture, we selected 10yearold Pyrus betulaefolia for continuous subculture, and then counted the propagation coefficient and rooting rate of multiple shoots of different subculture passages. We also observed and recorded the morphological changes of leaves and measured the content of endogenous hormones. The results showed that: (1) the rooting rate of multiple shoots increased from 0 to 66.70% and the propagation coefficient increased from 2.13 in the first subculture to 4.20 through continuous subculture. (2) The leaves showed a lobes at 3rd subculture and then the degree of lobes gradually deepened; during the continuous subculture, leaf area and vein number of multiple shoots were decreased significantly, and leaf perimeter and leaf index showed a trend of decreasing firstly and then increasing. (3) The endogenous IAA content of multiple shoots reached 46.39 ng·g^-1 at 6th subculture, which was significantly higher than that of 0th subculture; with the increase of subculture passages, the endogenous ZR showed a trend of increasing firstly and then decreasing, and the endogenous GA₃ content did not change significantly, while the endogenous ABA content gradually decreased in the leaves; the values of IAA/ABA and IAA/ZR in the leaves increased with the number of subculture. (4) The ABA content and IAA/ZR of multiple shoots leaves showed significantly negative correlation and significantly positive correlation with rooting rate. The number of leaf lobes and IAA/ABA showed a significantly positive correlation with rooting rate, while the number of leaf veins showed a significantly negative correlation with rooting rate. It can be seen that continuous subculture can significantly improve the rooting ability of P. betulaefolia multiple shoots, and it is closely related to leaf morphology and hormone content and ratio of multiple shoots, which provides reference for vegetative propagation of difficult rooting plants.

Abstract:With potted seedlings of Cunninghamia lanceolata as the subject, this research measured and analyzed changes in the concentration and distribution of nonstructural carbohydrates (NSC) and the NSC pool in different tissues/ organs after shading and light restoration. The former treatment being achieved with 60% shadenet, normal lighting being the control; after 30 days of shading, some materials were put under light restoration for 20 days. In this way, this paper studied the NSC regulation mechanism of C. lanceolata seedlings after shading and light restoration. The results indicated that: (1) shading could significantly reduce the concentration of soluble sugar in tissues/organs of the seedlings, the amplitude of reduction in turn being: fine roots (71%) > currentyear needles (68%) > oneyearold needles (58%) > bark (57%) > xylem (55%) > coarse roots (45%); shadingcaused decrease of starch concentration was significantly sharper than that of soluble sugar; of all tissues/ organs, the margin of decrease in starch concentration in coarse roots was the smallest (50%), followed by xylem (72%), fine roots being the largest. (2) Under shading, NSC concentration in different tissues/organs of the seedlings all dropped by over 50%, but the survival of the seedlings remained 100%; the change of biomass in the seedlings after shading showed no significant difference, only NSC pool narrowed, and NSC relative distribution modified; after shading, NSC in different tissues/organs declined to varied degrees, NSC concentration of coarse roots being significantly higher than that of fine roots. (3) After light restoration, NSC concentration in the tissues/organs of the seedlings returned to an equivalent level with the control. According to the research, under shading conditions, seedlings of C. lanceolata could actively adjust their NSC distribution in different tissues/organs so that it remained in a certain range, thus enhancing their own adaptability to the shaded environment but not at the expense of growth.

Abstract:In order to provide a reference for the cultivation of ‘Liguangxing’ in Dunhuang area of Gansu Province, we used 8yearold ‘Liguangxing’ as the test material. During the flower bud expansion period, 0.1% (P1), 0.3% (P2) and 0.5% (P3) boron were sprayed. Besides, 50 (C1), 100 (C2) and 150 mg/L (C3) gibberellin were sprayed in the early blooming period. The fruit quality, fruit setting rate and nutritional growth index of ‘Liguangxing’ under different treatments were measured. The advantages and disadvantages of different treatments with principal components were analyzed. The results showed that: (1) the leaf area growth of ‘Liguangxing’ was significantly higher than that of CK under C1 concentration. Boron treatment with different concentration had inhibitory effect on leaf area growth. However, the fresh treetop growth rate of C1 and P2 was higher than that of other treatments. (2) Suitable concentration of boron and gibberellin can effectively reduce the abortion rate of ‘Liguangxing’ and improve the fruit setting rate of fruit trees. Boron treatment was the best at P3 concentration and gibberellin treatment was the best at C2 concentration. However, there was no significant difference in fruit setting rate between P3 and P2 treatments. (3) Boron and gibberellin could significantly improve the quality of plum and apricot fruit. The ratios of sugar to acid and soluble solids in C1 were significantly higher than that of CK. The contents of Vc and titratable acid in P2 treatment were significantly higher than that in others. The optimum concentration of gibberellin and boron can significantly promote the fruit weight, shape index and lateral diameter. (4) According to the comprehensive evaluation results of principal component analysis, the comprehensive scores of the treatment effects of each concentration were P2 (1.20), C2 (0.91), P1 (0.13), C1 (-1.01), CK (-1.68), P3 (-2.13) and C3 (-7.76) from high to low. The main components included soluble sugar, soluble protein and ratio of sugar to acid are higher, which could be used as an important basis for evaluating the quality of ‘Liguangxing’ fruit. It was found that spraying appropriate concentration of boron and gibberellin at flowering stage could effectively improve the growth status, fruit setting rate and fruit quality. In Dunhuang area of Gansu Province, spraying 0.3% boron at the stage of flower bud expansion and 100 mg/L gibberellin at the early stage of full bloom were the best.

Abstract:This study selected desert grasslands in Inner Mongolia, and designed three treatments: no grazing (NG), moderate grazing (MG), and heavy grazing (HG). The stoichiometric characteristics and synergetic relationship of nutrient elements C, N and P of dominant plant S. krylovii and soil were analyzed after five years, to reveal the mechanism of nutrient cycling in grazing ecosystem and provide theoretical basis for the utilization and restoration of regional grassland. The results showed that: (1) the species diversity of desert grassland was significantly higher than that of moderate and heavy grazing (P < 0.05). (2) The contents of C, N, C∶N, N∶P, C∶P in the soil all showed a trend of increasing firstly and then decreasing with the increase of grazing intensity, while the content of P in the soil increased with the increase of grazing intensity. (3) With the increase of grazing intensity, the contents of C in the aboveground part of S. krylovii decreased, and N, P, N∶P increased firstly and then decreased, while C∶P decreased firstly and then increased. The contents of C, N, N∶P in the underground part of S. krylovii have been increasing. P content firstly decreased and then increased, while C∶N, C∶P were contrary to the rule of P content. (4) Compared with the contents of elements in the aboveground part, the correlation between the content and ratio in the underground part of S. krylovii and the contents of elements in the soil is higher, which indicates that the root system of dominant plants in the desert grassland and its soil environment have certain cooperative change ability under grazing conditions.

Abstract:Using desert C₃ plant Reaumuria soongarica and C₄ plant Salsola passerina as materials, along the natural precipitation gradient in the arid desert region of Northwest China, the solitary and mixed R. soongarica and S. passerina roots, stems and leaf organs under different precipitation conditions we measured carbon, nitrogen, and phosphorus stoichiometry indicators, and analyzed their stoichiometric characteristics in different habitats in response to interspecific relationships and environmental stress. The results showed that: (1) with the increase of drought stress (decrease in precipitation), the C content of various organs of R. soongarica increased by 7.73% on average, and the N and P contents decreased by 6.20% and 10.61%, respectively; the C content of S. passerina increased by 7.36% on average, and the N and P contents decreased by 5.93% and 14.03%, respectively. The increased C content in the leaves of the two plants indicates that their photosynthetic rate is low and their growth is slow. However, they have a strong defense ability against the adverse external environment and can better adapt to the drought environment. (2) Drought stress changed the distribution patterns of C, N and P in different organs of R.soongarica and S. passerina, and the N content and N/P ratio were higher in leaves than that in roots. The N/P of R. soongarica and S. passerina was significantly higher in roots and leaves than that of stems, indicating different nutrient limitation in different organs of the two plants. (3) The contents of C, N and P in R. soongarica are higher than that in S. passerina, which indicates that R. soongarica has strong defensive ability, fast growth rate and strong ability to compete and utilize resources. C/N and C/P of S. passerina were higher than those of R. soongarica, indicating that S. passerina had stronger carbon assimilation ability and higher nutrient use efficiency. (4) Under drought stress condition, both R. soongarica and S. passerina showed a pattern of carbon accumulation and nitrogen and phosphorus limitation. They were inactive in nitrogen and phosphorus nutrient utilization, and were more balanced by the nitrogen and phosphorus limitation.

Abstract:Taking naturally distributed Dinochloa orenuda (strong climbing ability) and Bonia levigata (weak climbing ability) in Ganshenling, Hainan Island as the experimental materials, we investigated light response curve and the CO₂ response curve of leaves in February, April, July and November to analyze photosynthetic characteristics of climbing bamboo and their adaptation mechanisms to rainforests by using Li6400 portable photosynthesis system. Results showed that: (1) compared to B. levigata, D. orenuda generally had higher lightsaturated maximum net photosynthetic rate (P_nlmax), light saturation point (LSP), light compensation point (LCP), dark respiration efficiency (R_d) and stomatal conductance (Cond), but showed lower apparent quantum efficiency (AQE) and intercellular carbon dioxide concentration (C_i) determined in each month. (2)The P_nlmax, LSP, LCP, R_d, Cond, C_i and T_r of the two bamboo species determined in July were higher than those determined in other months, and the AQE and water use efficiency (WUE) determined in February were higher than those determined in other months. (3) The carboxylation efficiency (CE), CO₂saturated net photosynthetic rate (P_ncmax) and photorespiration rate (R_p) determined in each month of D. orenuda were higher than those of B. levigate. For the two bamboo species, the CO₂ saturation point and CO₂ compensation point determined in April were higher than those determined in other months, but their CE and P_ncmax were lower. In general, D. orenuda was a lightloving plant which had stronger photosynthetic capacity and adaptive capacity to CO₂ concentration changed, while B. levigata coexisted with other species in tropical rain forests due to its shadetolerant properties. The two bamboos both generally had stronger photosynthetic capacity during the rainy season than during the dry season. In the rainy season. two bamboos mainly increased their net photosynthetic rate by increasing LSP, Cond, and C_i, and during the dry season, photosynthesis was mainly maintained by reducing T_r and increasing WUE. Overall, Seasonal changes in photosynthetic characteristics of two bamboos were the result of the combined action of the environment and the physiological characteristics of the species. The two bamboos grown in the rainforest developed different survival strategies due to their different photosynthetic characteristics.

Abstract:Dorofeyukea kotschyi is an epipelic or epipsammic diatom. This paper introduces a recently erected diatom genus Dorofeyukea and studies the specimens of D. kotschyi from the East Dongting Lake National Nature Reserve using light and scanning electric microscopy. The results show that D. kotschyi possesses the following main characters: (1) ellipticlanceolate valves; (2) a butterflyshaped fascia, but not across the valve face; (3) radiate striae on the most valve surface where stria density is 20-22/10 μm, except at the two apices where striae are parallel; (4) the nearly rounded areolae and the inner areola openings covered by domeshaped hymens; (5) a pseudoseptum occurring at both apices. The features of the D. kotschyi population investigated in this study fit well the ones of the type population, and the genus Dorofeyukea is reported in China for the first time, thus, this paper in fact reports a new genus record and a new diatom record.

Abstract:The different colors of colored leaf plants are mainly affected by the genetic factors and the external environment. Therefore, revealing the coloring mechanism of colored plants from the molecular level has important theoretical and practical significance for selecting new varieties of colored plants and the application of colored plants. At present, the research on the coloration mechanism of colored leaf plants mainly focuses on pigment changes, photosynthetic characteristics, leaf structure and environmental conditions in leaves. In this paper, the research progress of chlorophyll metabolic pathway, carotenoid metabolic pathway, secondary metabolic pathway, photosynthesis and chloroplast development related structural genes and transcription factors regulation mechanism in leaf of colored leaf plant were summarized, and the future research directions were prospected. It provides a theoretical basis for cultivating new varieties of colored leaf plants, and provides reference for artificially regulating leaf color and directed genetic improvement of colored leaf plants.