Abstract:AGL16 is an important negative regulatory transcription factor that regulates stomatal density and ABA content in Arabidopsis, and plays an important role in drought resistance in Arabidopsis. In order to obtain Arabidopsis agl16 mutant material, we used cotton leaf crumple virus (CLCrV)mediated VIGE system to screen the target and knockout Arabidopsis AGL16 sgRNAs. At the same time, the intact editing vector was transformed into wildtype Arabidopsis by Agrobacteriummediated flower dip method, and Arabidopsis agl16 mutant was created and identified for drought resistance. The results showed that: (1) two sgRNAs that can target and knockout Arabidopsis AGL16 gene were obtained by CLCrVmediated VIGE system, while AtU626∷AtAGL16sgRNA135S∷Cas9Terp1300 editing vector was constructed to transform wildtype Arabidopsis Col0, and agl16 homozygous mutant (AGL16:4) with 4 bp deletion of the target site was screened. (2) The results of drought resistance phenotypic identification showed that after 18 days of drought treatment, most of the wildtype plants dried up and died, while the mutant plants had a relatively lightly stressed; After rehydration, the survival rates of wildtype and mutant plants were 34.5% (10/29) and 75% (27/36), respectively. (3) Compared with the wildtype, the number of stomata per unit area in leaves and the water loss rate of isolated leaves of AGL16:4 homozygous mutant plants were reduced under drought stress, but the seed amount per plant did not change significantly. The results showed that the drought resistance of AGL16:4 homozygous mutant was significantly enhanced compared with the wildtype, and the seed quantity was basically the same as that of the wildtype, indicating that AGL16 gene could be an ideal candidate gene for crop drought resistance breeding; The obtained agl16 mutant provides a favorable transgenic receptor material for the functional complementation verification of the AGL16 homologous gene cloned from crops in the future.

Abstract:Transcription factor HY5 (ELONGATED HYPOCOTYL5) played an important role in anthocyanin biosynthesis. In this study, we firstly cloned PdHY5 gene from the Populus deltoides ‘Quanhong’ and analyzed it by bioinformatics methods, we then transformed PdHY5 gene into tobacco by Agrobacteriummediated leaf disc method for functional analysis. The results showed that: (1) the open reading frame (ORF) of PdHY5 was 510 bp and encoded 169 amino acids. Comparison of amino acid sequences and phylogenetic analysis indicated that PdHY5 contained a conserved domain of bZIP family and had a closest relationship with PtHY5. (2) An overexpression vector pNP130235SPdHY5 was successfully constructed, and 4 tobacco transgenic lines (S1-S4) were obtained by hygromycin screening. (3) qRTPCR results showed that the expression of PdHY5 gene in the 4 overexpression lines was significantly higher than that of WT (wild type), with the highest expression of S4 and the least of S1. Whats more, the expression levels of several key genes participated in anthocyanin biosynthesis, such as CHS, F3H, and FLS in overexpression lines were significantly upregulated compared with WT. (4) The relative content of anthocyanin was significantly higher in transgenic tobacco lines S2, S3 and S4 compared with WT, increasing by 128.23%, 97.36% and 134.20%, respectively. This study indicated that overexpression of PdHY5 gene regulated the expression of structural genes in the anthocyanin biosynthesis pathway of tobacco itself, thereby promoting the accumulation of anthocyanins.

Abstract:CDPK (calciumdependent protein kinase) gene was proved to play an important role in the biological and abiotic stress of plants. In this study, Dendrobium ‘Rainbowcompactum’ was used as the experimental material, calciumdependent protein kinase genes were cloned by RTPCR and their bioinformatics analysis were carried out. The expression of CDPKs gene in different tissues and under different low temperature stress was analyzed by qRTPCR, which laid the foundation for the functional verification of the CDPK gene and the research on the molecular mechanism of cold resistance of Dendrobium spp.. The results show that: (1) DenCDPK1 (GenBankaccession number: MZ322902), DenCDPK2 (GenBank accession number: MZ322903), DenCDPK3(GenBank accession numbe: rMZ322904) were cloned, with 1 934, 1 971 and 2 302 bp in length, encoding 534, 541 and 536 amino acids, respectively. (2) Sequence identity analyses showed that the identity of DenCDPKs protein and corresponding CDPK protein of Dendrobium officinale were both higher than 97%, and DenCDPKs contained a STKc_CAMK domain and 4 EFhand domains. (3) qRTPCR analysis showed that DenCDPK1, DenCDPK2 and DenCDPK3 were all highly expressed in leaves, and lowly expressed in stems, flowers and stems, respectively. The expression levels of DenCDPK1 and DenCDPK2 in leaves of Den. ‘Rainbowcompactum’ were higher than those of other three tested varieties. After being stressed at 8 ℃ for 12 h, the expression of DenCDPKs in leaves was significantly higher than that in the control group, and the expression of DenCDPK3 reached the highest value at 0 ℃ for 12 h. (4) The relative electrical conductivity in the leaves of Den. ‘Rainbowcompactum’ was lower than those of other three tested varieties under normal temperature (25 ℃). After low temperature (8 ℃, 0℃) stress for 12 h, the relative electrical conductivity in the leaves was significantly higher than that of the control group, and showed an upward trend with the decrease of temperature. It is speculated that DenCDPKs genes may be involved in the response to low temperature stress of Dendrobium spp., especially DenCDPK2 may play an important role in the cold resistance process of Dendrobium spp..

Abstract:In order to study the role of the isoamylase gene (ISA3) in the metabolism of yam tuber starch, we used Bikeqi yam and Dahechangyu yam as the measure to determine the starch and its component content and isoamylase (ISA) activity. The RTPCR technology has been used to clone the open reading frame of ISA3. The bioinformatics analysis were performed. Expression of ISA3 gene in different swelling stages tuber and among different tissues of yam was analyzed. The results showed that: (1) the amylose, amylopectin and total starch contents of Dahechangyu yam are significantly higher than Bikeqi yam, and the starch content of the two varieties showed a trend of first increase and then decrease with the change of growth and development, it reached the highest level at 120 d after planting. However, the ISA activity of Bikeqi yam was higher than that of Dahechangyu yam during the whole expansion period. (2) We successfully isolated an isoamylase gene (ISA3) from yam variety Bikeqi and Dahechangyu. Its sequence length is 1 584 bp and encodes 527 amino acids. ISA3 is a hydrophilic protein and nontransmembrane structure. (3) In different periods of yam tuber expansion of 2 varieties with different starch contents, ISA3 gene expression increases first and then decreases in Bikeqi yam, but gradually decreases in Dahechangyu yam. It is expressed in the leaves, stem and tuber, and there is obvious tissue specificity. (4) ISA activity was extremely significantly and significantly positively correlated with yam starch content and amylose content. Nevertheless, ISA activity was negatively correlated with the expression of ISA3. This result suggests that ISA is involved in the synthesis of starch in tubers and play a key role in the synthesis of amylose, and ISA3 expression may play negative regulation of ISA activity and starch synthesis.

Abstract:Translation elongation factor EF1α (elongation factor 1 alpha) is one of the most abundant proteins in cells, which plays an important role in ensuring the correct decoding of mRNA to produce cellular proteins. In this study, the gene sequence of CsEF1α of coriander was cloned by RTPCR, and the structure, sequence characteristics, and phylogenetic evolution were analyzed by bioinformatics software. Meanwhile, the qRTPCR was used to detect the expression patterns of CsEF1α in coriander at different growth stages and different abiotic stress treatments. These provide the foundation for further research on the regulatory mechanism of the EF1α gene. The results showed that: (1) the CsEF1α gene sequence of coriander was cloned successfully. CsEF1α gene contained a 1 344 bp open reading frame encoding 447 amino acids. The molecular formula of CsEF1α was C₂₂₀₂H₃₅₄₄N₅₉₄O₆₄₄S₂₀, the protein molecular weight was 49.29 kD and the isoelectric point was 9.12. CsEF1α is a basic protein with the highest number of lysine (49, 11.0%) and the lowest number of tryptophan (3, 0.7%). (2) The protein of CsEF1α was mainly composed of random coils (36.91%) and αhelices (30.43%), and localized in the cytoplasm. Phylogenetic tree analysis showed that CsEF1α in coriander was closely related to carrots, wild tomatoes, artemisinin, and Gerbera. Promoter prediction found that the promoter of CsEF1α contained four plant growth developmental elements, three hormone response elements, and three stress response elements. (3) The results of the qRTPCR showed that the expression profiles of the CsEF1α increased with the growth of coriander and were consistent with the transcript abundance. The expression pattern of CsEF1α differed under four different abiotic stresses. With the increase of stress treatment time, the CsEF1α gene showed a tendency to increase and then decrease under salt stress, while it showed a tendency to decrease and then increase under low temperature, high temperature, and drought stress. These results showed that the CsEF1α gene in coriander is involved in the response to abiotic stresses. In conclusion, CsEF1α in coriander might play an important regulatory role in growth and development and abiotic stresses.

Abstract:bHLH93 transcription factor is involved in regulating the plant growth and development and various physiological processes in plants. The VvbHLH93 gene was cloned from Cabernet Sauvignon by RTPCR and analyzed by bioinformatics. The expression of VvbHLH93 in different tissues and fruits at different developmental stages was analyzed by qRTPCR, which laid a foundation for further exploring the function and mechanism of VvbHLH93 gene. The results showed that: (1) VvbHLH93 was cloned successfully. The full length cDNA of VvbHLH93 was 1 319 bp, containing a 939 bp open reading frame which encoded 312 amino acids. The relative molecular weight of VvbHLH93 was 35.18 kDa, and its isoelectric point was 4.68. There was no signal peptide or transmembrane domain in this protein, belonging to the bHLH family. (2) bHLH93 in Vitis vinifera L. was closely related to that in Nelumbo nucifera. VvbHLH93 possesses an acidic region in C terminus rich in serine and threonine putative phosphorylation sites. The promoter of VvbHLH93 gene contained light response element, low temperature, drought and GA response element. (3) qRTqPCR analysis showed that the expression of VvbHLH93 in Cabernet Sauvignon was tissuespecific, it was not expressed in leaves, and had the highest expression in stems. The expression level of VvbHLH93 was decreased continuously with the development and maturity of fruit, and it was basically 0 in the 5th week after young fruit stage (> 2 mm in diameter), showing a unimodal downward trend during seed development. Compared with the control group, the expression of VvbHLH93 was significantly decreased under low temperature stress, salt stress, high temperature stress and full irrigation stress. The study speculated that VvbHLH93 may be a negative transcription factor of grape stress resistance.

Abstract:In order to clarify the role of AKR gene in grape under abiotic stress, we identified the whole genome of grape AKR gene family (VvAKRs) by bioinformatics method, and verified its expression rule under abiotic stress. The results showed that: (1) there were 9 members of this gene family in the grape genome, mainly distributed on 5 chromosomes, the amino acid residues ranged from 275 to 2 686 aa, and the theoretical isoelectric point ranged from 5.1 to 9.1. (2) Phylogenetic analysis showed that the gene family was divided into 6 subgroups, and the sixth subgroup had the most VvAKR family members. (3) The codon bias results showed that the codon bias of grape AKR gene family was weak. (4) The collinearity analysis showed that among the nine AKR genes, only the correlation between VvAKR8 and VvAKR9 was collinearity. (5) The results of qRTPCR analysis showed that the responses of grape AKR family genes to hormone and abiotic stress were different in different tissues of roots, stems and leaves. Under abiotic stress, VvAKR1, VvAKR3, VvAKR8 and VvAKR9 genes were highly expressed in grape roots, stems and leaves; under hormone treatment, VvAKR3, VvAKR6 and VvAKR8 genes were highly expressed in root tissues under ABA, MeJA and SA treatments; VvAKR3 genes were highly expressed in stem tissues under NAA and GA₃ treatments; and VvAKR1 genes were highly expressed in leaf tissues under various hormone treatments. This experimental study shows that grape AKR gene family played different roles in response to grape abiotic stress, which provided a theoretical basis for the study of grape stress resistance.

Abstract:To reveal the developmental similarities and differences of gemmae between various fern species and to compare the developmental characteristics of gemmae in fern and bulbils in angiosperm, we used morphological observation, paraffin sectioning and scanning electron microscopy to observe the gemmae development and vegetative organs of Monachosorum henryi (Dennstaedtiaceae) in this study. The results showed that: (1) leaves of M. henryi were thin, composed of 7-8 layers of cells, with stomata distributed on lower epidermis, and without obvious differentiation between palisade tissue and sponge tissue. (2) The leaf axis of M. henryi contains an “heart” shaped vascular bundle, and the base of the petiole contains two vascular bundles from the base to the middle; mature roots can see obvious vascular tissue, without marrow. (3) Leaf development of M. henryi should be divided into five stages: the active recovery, the rolling fist, the leaf unfolding, mature and senescence period. The gemmae development in leaves started from the leaf unfolding stage, and should be divided into four periods: primordial development, gemmae differentiation, gemmae expansion, and gemmae maturation stage. (4) The gemmae primordium of M. henryi was originated from the parenchyma cell under the epidermal cells at the bifurcation between the leaf axis and the plume leaf. Multiple nonleaflike primary “leaves” differentiated and showed the overall “anchor” shape. The gemmae falls into the soil after mature or germinates on mother plant.

Abstract:The fruits of 12 grape varieties at the maturity stage were used as materials in this study. We used texture profile analysis (TPA) to determine flesh texture parameters such as hardness, elasticity, adhesiveness, stickiness, chewiness, and resilience, and evaluated the flesh texture and grade. The contents of flesh cell wall components (watersoluble pectin, protopectin, cellulose) and the activities of PG, PEP, PL, CE, and other key enzymes were determined by Elisa kit, and the differences among different varieties were analyzed. We used the tissue section method to observe the microstructure of grape pulp tissue cells, and measure the cell structure parameters such as cell area, circumference, length, width, and cell shape parameters such as aspect ratio and roundness, to analyze the differences of cell structure among different varieties. To further explore the relationship between cell wall components, key enzyme activities and cell morphology parameters and grape flesh texture, and provide reference for grape flesh texture quality control. The results showed as follows: (1) the flesh texture of 12 grape varieties was divided into 5 types, crisp, fragile and crisp, firm, medium and soft; (2) There were significant differences in the interstitial parameters, the contents of the components of pulp cell wall, the activities of key enzymes, cell morphological parameters and microstructures among different cultivars. Among the texture parameters, the TPA hardness, adhesion and chewability of fruit peeled had the largest differences, with the coefficient of variation reached 75.16%, 65.57% and 65.25%, respectively. Among the cell wall components and key enzyme activity indexes, cellulose content and watersoluble pectin/original pectin had the greatest differences, with coefficients of variation reached 38.12% and 37.59%, respectively. The cell area showed the largest difference among the cell structure indexes, with a variation coefficient of 64.91%. (3) There were significant or extremely significant correlations between texture parameters measured with and without skin and texture rating score, and the correlation coefficients of TPA hardness, stickiness and chewiness were the highest (0.578^*, 0.751^* and 0.789^**, respectively). There was a significant positive correlation between flesh cell wall components' protopectin content and texture rating score (0.679^*), and a significant negative correlation between watersoluble pectin/protopectin and texture rating score (-0.860^**), while the contents of other cell wall components and activities of 4 key enzymes had no significant correlation with flesh texture score and texture parameters. The correlation between the structural parameters and shape parameters of flesh cells and the rating score of texture and texture parameters was not significant. The flesh cell area of the soft crispy flesh varieties was significantly larger than that of other varieties, and the flesh cells of soft flesh varieties were disintegrated and the cell wall boundary was unclear. Research shows that the hardness of grape flesh is mainly affected by pulp cell degradation, the higher the ratio of watersoluble pectin to original pectin, the softer the flesh texture. The ratio of watersoluble pectin to original pectin, TPA hardness, stickiness and chewiness measured with skin could be used as quantitative evaluation indexes of grape flesh texture.

Abstract:In order to study the capability and mechanism of different grape rootstocks under salt stress, we used 13 grape rootstocks as experimental materials. The grapevines were supplied with 1/2 Hoaglands nutrient solution with 100 mmol/L NaCl, grapevine rootstocks which were not treated with 100 mmol/L NaCl were used as control. After 20 fully expanded true leaf, we investigated the relative conductivity, osmotically regulates substance content, MDA content, antioxidant enzyme activities of leaves and roots. The results showed: (1) the leaves of the ‘18808’, ‘3309C’ and ‘140R’ treatment groups were almost completely shed, and a small number of leaves fell off in the ‘Beta’, ‘5BB’ and ‘Dogridge’, and the leaf wilting phenomena of ‘10114’ and ‘110R’ were the least until grape rootstock leaves to the end of the salt stress treatment. (2) Under salt stress, the relative conductivity of leaves of the varieties with poor salt tolerance such as ‘3309C’ and ‘140R’ was greater than 90%, and the relative conductivity of leaves of the varieties with strong salt tolerance such as ‘10114’ and ‘110R’ was about 60%. At the same time, with the increase in salt stress treatment days, the MDA content of ‘110R’ showed a clear upward trend. (3) Under salt stress, the higher salttolerant varieties of ‘10114’ and ‘110R’ produced more of osmoregulatory substances such as soluble proteins, soluble sugars and proline. The ‘3309C’ cultivar with poor salt tolerance has accumulated more reactive oxygen species, causing significant lipid film peroxidation, which seriously affects the normal metabolism of rootstock. (4) Under salt stress, ‘10114’ improved the activities of antioxidant enzymes such as SOD and POD, removed excessive reactive oxygen in the body and maintaining the stability of the cell membrane. The results show that grape rootstock varieties ‘10114’ and ‘110R’ can actively accumulate more osmotic regulatory substances under salt stress, enhance their antioxidant enzyme activities, show strong osmotic regulation and antioxidant capacity, and effectively resist the damage caused by salt stress. Therefore, it can be used as a rootstock variety in viticulture in the salinized areas of the northwest region.

Abstract:In this study, the cucumber cultivar ‘Zhongnong 18’ and pumpkin cultivar ‘Jingxinzhen No. 5’ were used as materials, and the intact pumpkin seedlings (P) and the seedling with one cotyledon and apical meristem being removed (/P) were used as control, two grafting combinations including cucumber/pumpkin (C/P) and pumpkin/pumpkin (P/P) were set up, using the onecotyledon splice grafting method. The changes of the morphological indexes and starch metabolism in the rootstock cotyledon of grated seedlings were detected, and the effects of removing rootstock cotyledon on the growth of grafted seedlings were analyzed. The major purpose of this study is to reveal the role of starch metabolism of rootstock cotyledons in the growth of cucumber grafted seedlings, and thereby provide a theoretical basis for improving the quality of cucumber grafted seedlings. The results revealed that: (1) after grafting, the fresh weight and area of rootstock cotyledon of C/P and P/P seedlings increased rapidly, and the net increase in fresh weight and area decreased in this order: /P > C/P > P/P > P. (2) After grafting, the starch content in the rootstock cotyledons of C/P and P/P seedlings decreased during the early healing stage ［0-3 days after grafting (dag)］. Then the starch accumulated rapidly until 13 dag, when starch was gradually decreased. The starch content and its starch branching enzyme (SBE, for starch synthesis) and βamylase (βAL, for starch hydrolysis) activities in C/P rootstock cotyledon were significantly higher than that in P/P seedlings. (3) Removal of rootstock cotyledons at 0-10 day could significantly inhibit the growth of scion and roots in C/P grafted seedlings. Also, the root vigor, as well as the soluble sugar content and CWIN and HXK gene expression levels were significantly repressed. Removing the rootstock cotyledon at 0 dag led to the strongest inhibition effect. These results suggested that in the C/P grafted seedlings, rootstock cotyledon can serve as a storage organ. During early growth of grafted seedlings, the photosynthetic products can be stored as starch, and then the stored starch is hydrolyzed into monosaccharides, which can be used for the rapid growth of scion and roots of grafted seedlings.

Abstract:In order to reveal the influence mechanism of fulvic acid on the photosynthesis and antioxidant enzyme activity of Avena sativa under drought stress, this study selected A. sativa variety ‘Yanke 2’ as the material, adopted pot experiment, took normal water supply (75% of field capacity) as the control (CK), set drought stress treatment (45% of field capacity, D0), D0 and spraying fulvic acid of different concentrations (0, 200, 400, 600, 800, 1 000 mg/L) treatment (D1-D5), The dry and fresh weight, photosynthetic performance and antioxidant enzyme activity of A. sativa were measured. The results showed that: (1) compared with CK, under drought stress, the aboveground fresh and dry weight, leaf photosynthetic pigment content, net photosynthetic rate (P_n), transpiration rate (T_r), stomatal conductance (G_s) of A. sativa seedlings were significantly reduced, and F_v/F_m, qP, ETR and Φ_PSⅡdecreased significantly. The activities of SOD, POD and CAT in leaves were increased by 25.68%, 19.98% and 7.29% respectively. (2) Compared with D0, after spraying 600 mg/L fulvic acid, the shoot fresh weight and dry weight of A. sativa seedlings were significantly increased by 28.59% and 39.13%, respectively. Chlorophyll a, chlorophyll a+b, carotenoids content and P_n, G_s, T_r, F_v/F_m, Φ_PSⅡ and ETR increased by 25.17%, 21.03%, 47.37% and 74.38%, 26.47%, 43.34% and 6.49%, 69.57% and 70.71%, respectively, and C_i, F_o and NPQ decreased by 19.52%, 13.32% and 43.75%, respectively. (3) Under drought stress, the activities of SOD, POD and CAT in leaves of seedlings sprayed with fulvic acid of different concentrations were significantly increased compared with D0 treatment. Among them, the activities of SOD, POD and CAT in leaves sprayed with fulvic acid of 600 mg/L were the highest, which were significantly increased by 12.19%, 76.57% and 55.26% compared with D0 treatment. The study shows that foliar spraying suitable concentration of fulvic acid can improve the photosynthesis and antioxidant capacity of A. sativa seedlings under drought stress, alleviate the damage of drought to A. sativa seedlings, and then promote the growth of A. sativa seedlings, and the effect of foliar spraying of 600 mg/L fulvic acid is the best.

Abstract:Minqin field and potted Agriophyllum squarrosum were used as the research objects. The control, wind retaining wall, watering and watering + wind retaining wall treatments were set under natural conditions, and the wind speed (0, 6, 8, 10 and 14 m·s^-1) and the blowing time (0, 15, 30 and 45 min) were set under the drought and watering environments in the wind tunnel, respectively. To investigate the effects of windsand flow and drought stress on photosynthesis of A.squarrosum, we measured the photosynthetic physiological characteristics of A.squarrosum by LI6400 portable photosynthetic apparatus. The results showed that: (1) under the natural field condition, the P_n diurnal progression of control, windretaining wall and watering treatments showed “double peak” curves, while it showed “single peak” curve in the windretaining wall + watering treatment. The peak value of windretaining wall was higher than that of the control, and the “lunch break” time of watering treatment was later than that of the control. The diurnal trends of G_s, T_r and WUE were similar to those of P_n, while the diurnal trends of C_i were opposite. The daily mean value of WUE was the highest in the retaining wall treatment, the daily mean value of T_r was the highest in the watering treatment, and the daily mean value of P_n and G_s were the highest in the retaining wall + watering treatment. (2) Under the watering condition, P_n and G_s increased under the low speed (6 m·s^-1) sand flow stress, then decreased with the increase of wind speed, T_r increased with the increase of wind speed, and WUE decreased gradually. Under drought conditions, P_n, G_s and WUE decreased with the increase of wind speed, while C_i and T_r increased. At the same wind speed, P_n, G_s, T_r and WUE of the watering treatment were higher than those of the drought stress treatment, while C_i and WUE of the watering treatment were same to those of the drought stress treatment. (3) The photosynthetic performance of A.squarrosum was significantly decreased when it was blown by medium speed (8 m·s^-1) sand flow for 45 min under watering condition, and significantly decreased when it was blown by medium speed sand flow for 30 min under drought stress. The results showed that drought and windsand flow stress could inhibit the photosynthetic performance of A.squarrosum, while watering and retaining wall could improve the photosynthetic performance. The photosynthetic performance of A.squarrosum was significantly enhanced by lowspeed aeolian sand flow stress under watering condition, but decreased with the increase of wind speed under drought stress. Watering could prolong the tolerance time of photosynthesis to persistent wind sand flow stress.

Abstract:The seeds of Rheum palmatum, R. tanguticum and R. officinale were cultured with double layer filter paper and subjected to a series of NaCl stress concentrations (0, 100, 150, 200, 250 mmol/L), and salicylic acid (SA) solution of a series of concentrations (0, 50, 100, 150, 200, 250 mg/L) were used for seed dressing or soaking to carry out salt stress experiments. We measured seed germination and seedling growth indexes of three kinds of rhubarb to reveal the effects of exogenous salicylic acid on rhubarb seed germination and seedling growth under salt stress. Overall, the results showed that: (1) seed germination rates of three rhubarbs decreased with the increasement of NaCl concentration. The cotyledon, hypocotyl, root and seedlings length were all strongly inhibited with the increasement of NaCl concentration. (2) Under the condition of seed dressing, 200 mg/L SA treatment promoted the seedling growth of R. palmatum under 200 mmol/L NaCl stress; 250 mg/L SA inhibited the germination rate of R. tanguticum seeds under 200 mmol/L NaCl stress; 200 mg/L SA inhibited the germination potential of R. officinale seeds under 100 mmol/L NaCl, 150 mg/L SA inhibited the germination rate of rhubarb seeds under 100 mmol/L NaCl stress, 250 mg/L SA inhibited the seedling growth of rhubarb seedlings under salinity stress. (3) Under seed soaking conditions, 50 mg/L SA increased the germination rate of R. palmatum seeds under 200 mmol/L NaCl stress, and the growth of roots and seedlings was promoted by 250 mg/L SA treatment, and 250 mg/L SA promoted the growth of roots and seedlings of R. palmatum seedlings under 200 mmol/L NaCl concentrations; 200 mg/L SA promoted germination potential of R. tanguticum under 200 mmol/L NaCl stress, and the growth of roots and seedlings was promoted by 50 mg/L SA treatment; 50 mg/L SA promoted root and seedling growth of R. tanguticum under 200 mmol/L NaCl stress; 100 mg/L SA promoted the growth of roots and seedlings of R. officinale under 100 mmol/L NaCl stress. Therefore, it can be concluded that the three kinds of rhubarb seeds had the same response trends to salt stress, but had great differences in response to seed dressing and seed soaking with different concentrations of SA.

Abstract:To understand the genetic diversity and variation types of the phenotypic traits of Gleditsia sinensis in Guizhou Province, and to lay a theoretical foundation for genetic improvement, germplasm identification, parental selection and cultivar breeding, we selected 70 individuals from 7 wild G. sinensis populations in Guizhou Province as the research objects in this study. The 10 species phenotypic traits of G. sinensis populations were systematically analyzed and comprehensively evaluated by means of ANOVA, principal component analysis, correlation analysis and multitrait comprehensive evaluation. The results showed that: (1) the differences of the phenotypic characters of G. sinensis reached the highly significant level within the population (P < 0.01), and the differences of other phenotypic characters among the populations, except for the number of seeds produced, seed width, seed length plus width and product seed aspect ratio (P < 0.01). (2) The average coefficient of variation of each character in seven populations was 21.16%, and the highest coefficient of variation was found in Kaili (P4) population (24.44%). The variation of pods among populations (29.22%) was higher than that of seeds (11.04%), and the variation mainly came from within population. (3) Correlation analysis showed that there were different degrees of correlation between the traits of G. sinensis seed. Principal component analysis showed that the cumulative contribution rate of the first four principal components (seed size, number of seeds produced by single pod, seed morphological index factor, pod length and seed thickness related factors) was 69.783%, which could basically reflect most information of the phenotypic traits of G. sinensis. According to the comprehensive evaluation of 10 species and fruiting traits of G. sinensis wild population, the comprehensive evaluation of species and fruiting traits of G. sinensis from Huishui County (P7) population was the highest. The results showed that wild G. sinensis in Guizhou Province had abundant phenotypic variation among and within population, and the variation within populations was greater than that between populations, and the variation mainly came from within population.

Abstract:Community biomass and species diversity are important indicators to characterize the quantitative characteristics of grassland ecosystems. This study conducted in the grasslands of the Tworiver Source grazing areas in the southern Altai Mountains of Xinjiang and a survey of grassland vegetation in different grazing areas of the Tworiver Source using the sample method, analyzed the changes in biomass and species diversity in the study area, and explored the correlation between the two and environmental factors, in order to provide a theoretical basis for the conservation of grassland community species and sustainable use of grassland. The results showed that: (1) there were differences in community cover, height, plant density, aboveground biomass and biomass per unit of cover among different grazing areas in the Tworiver Source. (2) The aboveground biomass of grassland communities in the Tworiver Source rangelands was significantly and positively correlated with community cover and plant density (P<0.05), and aboveground biomass was mainly influenced by the cover of grassland communities. The species diversity index varied somewhat among the different grazing areas, but the species distribution was relatively uniform. (3) Grassland community biomass and species diversity in the Tworiver Source rangelands are mainly influenced by temperature and precipitation.

Abstract:Deciduous oak forest is a typical secondary forest and an important group of deciduous forest in west Guangxi. In this study, we used a typical sample method to investigate deciduous oak forest community in West Guangxi, and analyzed the species composition, floristic components, species diversity characteristics and the relationship between the deciduous oak forest community and topographic factors. This study can provide scientific basis for the conservation and restoration of plant diversity in the south subtropical region of West Guangxi. Results showed that: (1) there were 269 species of vascular plants in deciduous oak forest, belonging to 178 genera and 80 families. (2) The spermatophyte flora was mainly influenced by Pantropic and North Temperate and its variations, which reflected a certain degree of transitional nature. (3) Based on cluster analysis, the deciduous oak forests could be classified into 4 types: Quercus yunnanensis forest, Quercus variabilis forest, Quercus fabri forest and Quercus acutissima forest. The species diversity of Q. fabri forest was the highest among all deciduous oak forests, and the diversity index of the shrub layer was significantly higher than the tree layer and herb layer. (4) The DCA ordination results indicated that longitude, latitude and altitude were the important topographic factors affecting the species diversity in different levels of deciduous oak forest community. The species diversity of tree layer was significantly correlated with longitude and latitude, shrub layer species diversity was correlated with latitude and altitude, and herb layer species diversity was correlated with longitude, latitude and altitude.

Abstract:Coelonema draboides is an endangered plant endemic to the Qilian Mountains. Prediction of potential suitable areas of C. draboides can provide important reference for conservation and research of C. draboides. Based on geographical distribution records and environmental factor variables, we used MaxEnt and ArcGIS models to simulate the suitable distribution areas of C. draboides in the Qilian Mountains under three climate scenarios, namely the present and future (2050s, 2070s) RCP2.6, RCP4.5 and RCP8.5, using 41 effective distribution points and 28 environmental factors. The leading factors affecting the distribution were screened. The results show that: (1) the mean value of AUC of training data sets is 0.948, and the mean value of random error is 0.043, so the MaxEnt model has a high simulation prediction accuracy. (2) The main factors affecting the geographical distribution of C. draboides were altitude, diurnal range of average temperature, isotherm, precipitation in the wettest month and soil organic matter, which accounted for 87.4% of the total contribution rate. (3) When the altitude is 3 000-4 000 m, the average daily temperature range is 10-12 ℃, the isotherm is 32-35, the precipitation in the wettest month is 140-160 mm, the soil organic matter is 1.2%-1.5%, and the annual average temperature is 0-25 ℃, it is suitable for the growth of C. draboides. It is speculated that C. draboides is suitable for growing in low heat, large daily temperature difference and small annual temperature difference, cold and semihumid plateau climate. (4) Under the current climate conditions, the potential geographical distribution of C. draboides was mainly located in the eastern and southern parts of Qilian Mountains. With the change of climate and time, the potential suitable area of C. draboides decreased, and the highly suitable area in the southern part of Qilian Mountains shrank to the north, and most of them were concentrated in the Qilian Mountain protection area. (5) In the future, it can be considered to focus on protecting the species in the Qilian Mountains Reserve, and the southern part of the Qilian Mountains Reserve can be used as a protected area for in situ protection.

Abstract:Grimmia caotongiana D. P. Zhao, S. Mamtimin & S. He, a new species of Grimmiaceae from Xinjiang Uyghur Autonomous Region of China, is described and illustrated here. The new species is most similar to Grimmia anodon Bruch & Schimp., but is distinguished by the absence of hair points in both vegetative and perichaetial leaves, the leaf margins narrowly recurved at middle and lower part, and the basal juxtacostal cells mostly hyaline, with walls distinctly thicker than those of basal marginal cells. Light microscope photographs of the significant characters are provided and its distinctions from closely related taxa are discussed.

Abstract:The heterotrimeric GTPbinding protein (G protein) mediated signal transduction is a key component in the regulation of growth, development and stress response in eukaryotes. Recent studies have shown that heterotrimeric G proteins consist of three subunits: α, β and γ. The core components and the basic biochemical properties of G proteins are conserved in animals and plants. However, new regulatory mechanisms of G proteins in plants have been revealed. G proteins have been identified as essential regulators in many agronomic traits, including seed yield, organ size, biological and abiotic stress, nitrogen use efficiency and so on. Therefore, studies on G proteins have become a hot area in plant science. In this review, we summarized the basic composition and the structure of G proteins, the acting mode of G proteins in animal and plants, and the function of G proteins in the regulation of plant growth, development, and stress response including drought, temperature and salt, with an aim to offer a reference for related research and provide a theoretical basis for crop breeding by using G proteins.