Abstract:1deoxyDxylose5phosphate synthase (DXS) is the first ratelimiting enzyme that controls the synthesis of plant terpenes in the methylDerythritol4phosphate (MEP) pathway. In this study, the sequence characteristics and bioinformatics of DfDXS gene of Dryopteris fragrans were analyzed, and its expression patterns under exogenous hormone, drought, salt stress, high and low temperature treatments were analyzed by qRTPCR technique, for exploring the role of DfDXS gene in terpenoid biosynthesis and stress resistance mechanism. The results showed that: (1) DfDXS1 fulllength 2 139bp encodes 712 amino acids, and DfDXS2 fulllength 2 160 bp encodes 719 amino acids. Domain analysis showed that it had a typical conservative domain of transketolase, including thiamine pyrophosphate binding site and transketolase domain. The genetic relationship is close to that of Selaginella moellendorffii DXS, Ginkgo biloba DXS1. (2) Under the treatment of salicylic acid (SA), the relative expression of DfDXS increased at first and then decreased; abscisic acid (ABA) inhibited the expression of DfDXS; DfDXS1 and DfDXS2 responded strongly to methyl jasmonate (MeJA) treatment, and the relative expression level of DfDXS1 was significantly higher than that of the control; Ethephon (Eth) inhibited the expression of DfDXS, but the expression of DfDXS1 was higher than that of the control at 3 h. (3) Polyethylene glycol (PEG), high temperature and low temperature all upregulated the expression of DfDXS1. The results showed that DXS gene plays a role in terpenoid synthesis and stress mechanism. This study provides a basis for further analysis of the molecular mechanism of stress resistance of D. fragrans.

Abstract:The purpose of this study is to lay a foundation for subsequent studies of antibacterial activity of pathogenesisrelated protein PR10 through exploring the ribonuclease activity of a PR10 gene in Picea asperata. This study cloned the full length of cDNA sequence of a PaPR10 gene using the annual needles of P. asperata as material by RTPCR technique. The specific primers were designed based on the sequence of PaPR10 which was significantly upregulated in response to the infection of spruce needlefalling pathogen (Lophodermium piceae). In addition, the sequence characteristics of the PaPR10 protein were predicted by bioinformatics software. The PaPR10 gene was prokaryotic expressed and purified, and the ribonuclease activity of the purified protein was detected by substrate method. The results showed: (1) the ORF of PaPR10 gene (GenBank accession number: OM743228) was 456 bp, and encoded 151 amino acids with a relative molecular weight of 16.52 kD and a theoretical isoelectric point of 5.73. (2) The PaPR10 protein had no signal peptide, no transmembrane region and was in the cytoplasm. It had a typical conserved domain of pathogenesis related protein Bet_v_1 family, a glycinerich PLoop conserved domain. However, there was a base mutation in the PLoop domain of PaPR10 protein. The results of phylogenetic analysis showed that PaPR10 protein had high similarity with some PR10 proteins in gymnosperms such as Picea crassifolia and some bryophytes. (3) The PaPR10 protein coexisted in the form of soluble and inclusion bodies with the induction of IPTG. In addition, the expression was the best when the final concentration of IPTG was 0.8 mmol/L at 30 ℃ for 10 h, but the purified PaPR10 soluble protein had no ribonuclease activity. The PaPR10 protein does not have ribonuclease activity.

Abstract:Enolase (ENO), as an enzyme in the glycolytic pathway, is involved in plant development and can respond to abiotic stresses. In this study, the cadmium (Cd) hyperaccumulator plantpokeweed (Phytolacca americana L.) was used as material. According to the transcriptome data of pokeweed, the specific primers were designed and the PaENO gene was isolated from pokeweed leaves. Then the sequence analysis, prokaryotic expression and purification, expression pattern analysis and Cd resistance assay were performed. This will provide a basis for further study on the enzymatic activity of PaENO protein and the mechanism of PaENO gene in response to Cd stress. The results showed that: (1) PaENO gene (GenBank accession number JN656932.1) was successfully cloned and the open reading frame (ORF) of the gene was 1 335 bp, which encoded 444 amino acids. (2) The multiple sequences alignment analysis indicated the identity of PaENO protein and McENO protein of Mesembryanthemum crystallinum was the highest, which reached 93.47%. Phylogenetic analysis showed that PaENO protein had closest homology with M. crystallinum, Beta vulgaris and Spinacia oleracea, and they belonged to the same evolutionary branch. (3) Realtime PCR results showed that the expression level of PaENO gene was the highest in pokeweed leaves, 2.5 times that of roots, followed by that in roots, and the lowest in stems, only 1/5 of that in roots. After Cd treatment, the expression level of PaENO gene was significantly increased. At 2 h, the expression level of PaENO gene rapidly increased to 9.54 times of that before Cd treatment (0 h), and decreased to 3.12 times and 2.89 times of that (0 h) after Cd treatment at 12 h and 24 h, respectively. This indicated that PaENO gene was involved in the response to Cd stress in pokeweed. (4) The prokaryotic expression vector pET28aPaENO was successfully constructed and transformed into E. coli BL21(DE3) competent cells. After induction by IPTG, the target protein band appeared at about 50 kD. Then, the E. coli cells were disrupted by sonication, and the supernatant and precipitate were collected after centrifugation. SDSPAGE analysis showed that PaENO was expressed in both the supernatant and the precipitate, and the expression level of PaENO was higher in the supernatant. The purified PaENO protein was obtained by using Ni affinity chromatography kit. The results of Cd resistance assay preliminarily confirmed that the expression of PaENO protein can significantly improve the resistance of E. coli to Cd. The study suggested that PaENO protein may play a regulatory role in pokeweed to cope with Cd stress in the form of transcription factor (PaMBP1).

Abstract:In this study, combined with Rosaceae database, through multiple sequence alignment, expression analysis and validation, we screened the defenserelated Marker genes and corresponding primers in the genome of apple (Malus domestica) and pear (Pyrus bretschneideri). We took the suspension cells of Duli and DongbeiShanjingzi as materials, treated with 20% metabolites of Valsa canker (Vp), and analyzed the expression patterns of marker genes in response to Vp signal by realtime fluorescent quantitative PCR (RT qPCR), which lays a foundation for the rapid detection of disease resistance reaction of apple and pear and systematic study of resistance mechanism to Vp of Duli.The results showed that: (1) a total of 15 Marker genes and corresponding primers for salicylic acid (SA), jasmonic acid (JA), ethylene (ET), systemic acquired resistance (SAR) response, pathogenassociated molecular patternprimed immune response (PTI), phycocyanin and defenserelated signals were screened by search and comparison. (2) The Cq values ranged from 18 to 25 at the cDNA concentration of 100 ng·μL^-1 for each treatment, and the PCR amplification efficiency was high, which indicated that the primers of the 15 Marker genes could accurately reflect the activation of the resistance response and could be used as Marker genes for the respective signaling pathways. (3) Compared with control, the accumulation of ROS in suspension cells of Duli after Vp metabolite treatment showed a significant increase with the treatment time, and the value of ROS signal reached 3.2 times of the control at 6 h, show that Vp metabolite activates the plant immune response (PTI), which induce the burst of ROS. (4) RT qPCR analysis showed that Marker genes of SA, JA, PTI, SAR, Rgene, phytogenesis and defenserelated signaling pathways were upregulated in Duli suspension cells after Vp metabolite treatment, among which, expression of SA, JA and SAR related genes ChiV (Chitinase class V), LOX1 (Lipoxygenase 1), PR4 (PathogenesisRelated 4), and defense response related gene PAL1 (Phe Ammonia Lyase 1) were robustly induced, the highest levels climbed to 1718-, 691-, 1072- and 6369fold of the control, respectively. The results shown that it mainly activated genes of SA, JA, SAR and defenserelated signaling pathways when Duli subjected to Vp metabolite, and then resist the further invasion of pathogens which in turn were able to resist further invasion of the pathogen. It was found that SA, JA, SAR and defense response signals were involved in the response of Duli to Vp, thereby improving its disease resistance.

Abstract:In order to identify the dehydration responsive element binding (DREB) genes in response to salt stress from the genomewide and transcriptome levels in wheat, this study performed transcriptome sequencing on the Illumina platform for roots of a salttolerant material CH7034 treated with salt stress at seedling stage, from which information on expression and alternative splicing of the TaDREB family were isolated and their downstream target genes were predicted. Finally, the TaDREBs and predicted targets in response to salt stress were verified by qRTPCR. The results showed that: (1) 48 DREB members (204 copies) named TaDREB1-TaDREB48 were identified in wheat and distributed on 21 chromosomes. (2) The TaDREB family was divided into 14 groups (G1-G14). The transcription levels of TaDREB members belonging to G2, G5, G10 and G14 did not change significantly after NaCl stress, while 25 TaDREB members from the rest of the groups showed different degrees of response to salt stress. Among them, 9 members were continuously upregulated after salt stress (containing 5 new reporter genes), and 2 members were continuously downregulated. The protein encoded by the downregulated member TaDREB35 might be degraded by a wheat RINGtype E3 ubiquitin ligase based on the protein interaction prediction result. (3) 9 members, including TaDREB3, TaDREB6, TaDREB16, TaDREB19, TaDREB21, TaDREB24, TaDREB25.12, TaDREB43 and TaDREB47, underwent alternative splicing changes after salt stress. (4) Based on the transcriptome, 3 differentially expressed genes TaRD29, TaGLOS and TaCKX with DRE/CRT elements in 2 000 bp region upstream of their start codon and the same expression trend between A/B/D subgenomes were selected as candidate targets. (5) qRTPCR verification results showed that the expression levels of TaDREB16 and the upregulated members except TaDREB19 displayed continuous upward trend; only TaDREB25 and TaDREB35 among the downregulated members displayed continuous downward trend; and the expression levels of the three predicted target genes continued to increase, which was consistent with the transcriptome sequencing results. The 11 salt stressresponsive TaDREB members and the 3 predicted targets identified in this study will lay the groundwork for the analysis of the salt tolerance mechanism and molecular breeding in wheat.

Abstract:In order to make full use of the wild resources of Erianthus fulvus and mining valuable resistance genes to enrich the candidate gene library of transgenic sugarcane breeding, we cloned MYB gene from E. fulvus ‘991’ by combined with the transcriptome analysis and RTPCR technology. We also curried out bioinformatics analysis and stress expression analysis. This study provided theoretical foundation for further analysis cold tolerance mechanism of E. fulvus and transgenic sugarcane breeding. The results showed that: (1) E. fulvus MYB was successfully cloned and named EfMYB1(GeneBank ID: ON586646). (2) Bioinformatics analysis showed that the full length of EfMYB1 gene was 1 000 bp, had an ORF with 759 bp and encoded 251 amino acids. The EfMYB1 protein has a conserved SANT domain and multiple phosphorylation sites, and no transmembrane structure and signal peptide. The secondary structure and tertiary structure of EfMYB1 protein were mainly αhelix and random coil. EfMYB1 protein has the highest similarity and closest genetic distance with MYB of Miscanthus lutarioriparius. (3) The results of qRTPCR analysis showed that the relative expression level of EfMYB1 gene were gradually increased with continuous low temperature stress in root and leaf tissues of E. fulvus, and reached the largest level at 72 h, while almost unchanged in stem. In addition, EfMYB1 gene expression was induced by Methyl Jasmonate (MeJA) treatment, and reached the highest value at 6 h. But the expression level of this gene was significantly decreased under Abscisic acid (ABA) treatment. This study demonstrated that EfMYB1 gene belongs to low temperature stress response gene and may be involved in E. fulvus response low temperature stress.

Abstract:In this study, the MfMYB30 gene was cloned from Medicago falcata L. cv. Hulunbuir by RTPCR based on transcriptomic sequence, and the gene expression was analyzed by bioinformatics. The results showed that: (1) the ORF sequence length of MfMYB30 gene was 957 bp, encoding 318 amino acids, with molecular weight of 86.85 KD and theoretical isoelectric point of 5.11. MfMYB30 protein is a hydrophobic protein without transmembrane structure and signal peptide sequence. (2) Phylogenetic analysis showed that the MfMYB30 protein of M.falcata clustered into a group with close genetic relationship with MsMYB4 of Medicago sativa, AtMYB30 of Arabidopsis thaliana, CcMYB30 of Caja caja, MtMYB30 of Medicago truncatula and GmMYB60 of Glycine max. (3) Realtime quantitative PCR results showed that the relative expression level of MfMYB30 decreased first and then increased after different days of simulated cutting, and reached the peak value after 7 days of cutting. (4) By analyzing the subcellular localization of protoplasts in A. thaliana, it was found that the protein was located in the nucleus. It is speculated that MfMYB30 gene may play an important role in the response to cutting or grazing stress of M.falcata.

Abstract:In order to explore the expression of bHLH transcription factor in the process of iron deficiency retrieved green of pear leaves, we screened the key bHLH genes in response to the process to provide a theoretical basis for improving the iron deficiency resistance of pear varieties. Normal and chlorotic plants of ‘Dangshansuli’ (Pyrus bretschneideri Rehd.) were taken as test material. We sprayed 0.2% FeSO₄(2 g·L^-1 FeSO₄) solution on the chlorotic leaves and distilled water were used for both normal (N) and chlorotic (C) leaves as control during the growing season. The leaves and tender root hair of normal, chlorotic plants and retrieved green leaves on 3rd, 6th, 9th, 12th day after FeSO₄ application were taken as samples for transcriptome data analysis, and the differentially expressed bHLH genes were screened, supplemented by fluorescence quantitative PCR. The expression and biological characteristics of the genes in leaves and roots were analyzed, and the correlation with Fe²⁺ content in leaves were analyzed. The results indicated that: (1) transcriptome data showed that there are 21 bHLH genes were significantly differentially expressed in chlorotic leaves at N, C and different stages after treatment with FeSO₄, involving 11 subclasses, and their motifs number ranged from 1 to 10. (2) qRTPCR showed that the expression of PbrbHLH7/29/41/104/119/122/128/155/183/191 in C leaves was significantly higher than that in N leaves. After FeSO₄ treatment, the expression of them were significantly lower than that in C leaves in different stages; In contrast, the expression of PbrbHLH15/46/53/69/78/89/115/137/144 in C leaves were significantly lower than that in N leaves. After FeSO₄ treatment, the expression of them were significantly higher than that in C leaves in different stages. (3) Consistent with the difference in the expression level in aboveground leaves, the expression of PbrbHLH29/41/119/128/155/183/191 in C roots were also significantly higher than that in N roots, while the expression of PbrbHLH53/89 in C roots was also significantly lower than that in N roots. (4) The correlation analysis showed that the content of Fe²⁺ in leaves was significantly negatively correlated with the expression of PbrbHLH41 and positively correlated with PbrbHLH78 in different stages after FeSO₄ solution treatment. In conclusion, the iron deficiency retrieved green of pear leaves regulated by exogenous FeSO₄ treatment may be closely related to the synergistic changes of bHLHs expression in leaves and roots of pear. PbrbHLH41/78 may play an important and antagonistic regulatory role in this process, which can be considered as candidate genes to study the mechanism of iron deficiency retrieved green of pear leaves.

Abstract:To investigate the molecular and physiological mechanisms associated with resistance diversity of different pineapple varieties, we utilized the two cultivars, PZ2 and PZ3 with differential stressresistance in this work to comparatively analyze the transcriptome and metabolome. (1) The transcriptome sequencing results showed that a total of 1 667 differential expressed genes were detected in PZ2 and PZ3 comparison group. In PZ3, 770 and 897 differential expressed genes were found to be up and downregulated when compared with PZ2, respectively, and 20 differential expressed genes were involved in adversity resistance, including ASR3, SOD1, POD48, HSP20, GSTF1, GSTU17, as well as WRKY and MYB transcription factor genes. (2) Metabolomics analysis indicated that a total of 208 differential metabolites were identified in PZ2 and PZ3 comparison group, 98 and 110 of those were upand downregulated in contents in PZ3 when compared with PZ2, respectively. Totally, 22 differential metabolites were found to be associated with adversity resistance, including amino acids and derivatives, lipids, flavanols, carbohydrates and glycosides. (3) It showed that the expression profiles of the eight genes revealed by qPCR were consistent with the corresponding RPKM values derived from RNAseq. (4) The correlation analysis showed that the pathways for coenrichment of differentially expressed genes and differential metabolites included flavonoid biosynthesis, phenylpropanoid biosynthesis, tropane, piperidine and pyridine alkaloid biosynthesis, and cysteine and methionine metabolism. It was found that the expression levels of abiotic stress responsive genes, antioxidant enzyme genes, as well as structure and regulatory genes response to stress, were higher in the pineapple cultivar with strong stress resistance than those of the cultivar with stresspoor resistance. Also, the contents of flavonoids, amino acids and derivatives, as well as lignans and lipids metabolites were higher than those of cultivar with stresspoor resistance. The data of this work would contribute to provide references for the comparative analysis of mechanism of pineapple varieties related to different resistance and to provide a theoretical basis for pineapple resistance breeding.

Abstract:Somatic embryogenesis is one mode of reproduction in plants, whereas ex vivo callus embryogenesis can perform plant regeneration, but also can be employed for genetic transformation. This study employed the widely targeted metabolomics and explored respectively proliferating and differentiating calli in the fern Ceratopteris richardii, aiming to investigate metabolic mechanisms for callus embryogenesis and thus providing materials for metabonomics of callus embryogenesis. The results found: (1) both the proliferating and the differentiating callus possessed the same metabolites, and there were some disease drugs among them such as actidione and 3［(Carboxycarbonyl)amino］Lalanine. (2) Each metabolites had different contents, but basically they were not altered between the proliferative and the differentiating stages. (3) Metabolites accumulated in the proliferating stage were predicted related to the ABC transporter protein pathway, while those in the differentiating stage probably concerning the flavonoid biosynthesis pathway. The research speculated transition from proliferating to differentiating phase of calli in C. richardii was a quantitative rather than a qualitative process in terms of metabolite alterations, and metabolomes of plant callus embryogenesis might be characterized by species specificity.

Abstract:In this test, seven pairs of SSR primers were selected to carry out molecular marker tests on 210 germplasm resources from 20 provinces, cities and autonomous regions in China, for studying the genetic diversity, kinship and genetic differentiation characteristics of the germplasm resources of Pistacia chinensis Bunge and constructing the DNA molecular identity card. It provides theoretical basis for the conservation and germplasm utilization of P. chinensis. The results showed that: (1) seven pairs of primers amplified 158 alleles from 210 germplasm, with an average number of 22.571 alleles per pair of primers. (2) The variation range of gene diversity (GD) was 0.654-0.913 with an average of 0.804. The expected heterozygosity (He) ranged from 0.257-0.771, with an average of 0.532. Polymorphic information content (PIC) ranged from 0.639-0.907, with an average of 0.784. (3) In terms of genetic diversity, the observed heterozygosity (Ho) ranged from 0.373-0.600, with an average of 0.520. The expected heterozygosity (He) was between 0.632-0.811, with an average of 0.737. According to the genetic differentiation index (Fst), the genetic differentiation value between populations in different regions of P. chinensis was between 0.015-0.099, and the genetic differentiation among populations was below the medium level. (4) Molecular variance analysis (AMOVA) showed that the genetic differentiation variation of P. chinensis was mainly within the population, accounting for 94% of the total variation, and the interpopulation variation accounted for 6%. (5) UPGMA clustering, PCoA analysis and population genetic structure analysis results were consistent, all germplasm were divided into two groups, the southwest population was a separate group, the other regions were a separate group. (6) Seven pairs of SSR primers were used to construct 210 DNA identification cards of P. chinensis germplasm.

Abstract:The seedling Chinese cabbage variety ‘Youlü No. 3’ was used as the material for pot experiment in a solar greenhouse. Under the blue film(B_flim), green film(G_flim), yellow film(Y_flim), red film(R_flim) and colorless film(W_flim), the leaves were foliar sprayed with 0, 12 and 24 mmol·L^-1 NaCl(B_flim0, B_flim12, B_flim24, G_flim0, G_flim12, G_flim24, Y_flim0, Y_flim12, Y_flim24, R_flim0, R_flim12, R_flim24, W_flim0, W_flim12 and W_flim24). The dry and fresh matter quality, leaf area, net photosynthetic rate (P_n), stomatal conductance (G_s), photosynthetic pigment, soluble sugar and free amino acid contents of the seedlings were measured, The compound regulation effect of foliar spraying NaCl on the growth and material accumulation of seedling Chinese cabbage under colored film spectrum was analyzed. The results showed that: (1) under the same film color, compared with the control (0 mmol·L^-1 NaCl), the growth indexes of seedling type Chinese cabbage were increased in different degrees under 12 and 24 mmol·L^-1 NaCl treatments, and the growth promotion effect of Y^film12 treatment was the largest. The fresh matter mass, dry matter mass, leaf area and soluble sugar content were significantly increased by 54.40%, 45.06%, 38.99% and 76.77%, respectively compared with W_film0 treatment; R^film12 and W^film12 treatments had greater growth promoting effect, but B^film12 treatment was more beneficial to the accumulation of free amino acids and soluble proteins and the formation of chlorophyll. (2)Under the same salt concentration (0-24 mmol·L^-1 NaCl), the dry and fresh matter accumulation of seedling Chinese cabbage under the five colored films was the largest in Y_film0 treatment, the larger in W_film0 treatment, the lower in R_film0 treatment, and the lowest in B_film0 and G_film0 treatment. (3) Spraying 12 mmol·L^-1 NaCl on the leaf surface not only has a strong superposition effect on the increase of soluble sugar content under the red film and photosynthetic pigment content under the blue film, but also has a strong compensation effect on the decrease of dry matter accumulation, soluble sugar content, P_n and G_s under the blue film, and leaf area under the red film, free amino acid content and soluble protein content. (4) The dry and fresh matter quality, soluble sugar content, photosynthetic pigment content, P_n and other dependent variables of seedling Chinese cabbage under colored film were not only regulated by direct path factors of R and fr spectral range parameters, but also by R∶FR and B∶R spectral proportion parameters; Leaf area is also regulated by spectral characteristic parameters such as YR, R∶ FR, B∶ y and B∶ G. It was found that under the five colored films, the foliar spraying of low concentration NaCl had a promoting effect on the growth and material accumulation of seedling Chinese cabbage, and there were both synergistic and compensatory effects. The yellow film, especially the foliar spraying of 12 mmol·L^-1 NaCl under the yellow film, had the best promoting effect on the growth of seedling Chinese cabbage.

Abstract:To study the effects of different light intensities (10% light, 40% light, 70% light and full light) on light utilization characteristics for oiltea, we used 2year old seedlings of oiltea cultivar ‘Changlin No. 4’ as pot experimental materials, which were performed in an artificial climate incubator. The results showed that: (1) the net photosynthetic rate (A_n), electron transfer efficiency (ETR), light compensation point (I_c), CO₂ compensation point (Γ), saturated light intensity (I_sat), saturated CO₂ concentration (C_isat), light respiration rate (R_p), dark respiration rate (R_d), light use efficiencies at leaf and plant levels were improved as light intensity increasing. (2) Under weak light condition, the photochemical efficiency of photosystem Ⅱ (F_v/F_m, Φ_PSⅡ) was improved as the photochemical quenching coefficient (qP) increased, while the nonphotochemical quenching coefficient (NPQ) decreased, and the absorbed light energy was more allocated to the photochemical dissipation and excess excitation energy. (3) The ability of light absorption was enhanced by increasing chlorophyll content, lightharvesting pigment molecule numbers (N₀), and intrinsic absorption crosssection (σ_ik). However, the effective light absorption cross section (σ_ik′) was increased, the minimum average life time at the lowest excited state (τ_min) was extended, and the lightharvesting pigment molecules at the lowest excited state (N_k) was increased as light intensity reducing. It can be concluded that the electron transfer between lightcapturing pigment molecules and the generation of photosynthetic electron flow were limited, and thus oiltea leaves were failure to coordinate the improvement of light energy capture and electron transfer efficiency under low light environment, which declined the ability of photosynthetic carbon assimilation and the light use efficiency.

Abstract:Seven treatments including control (CK), average fertilization (AF1, AF2), exponential fertilization (EF1, EF2, EF3 and EF4) were applied to the oneyearold container seedlings of Taxus madia × T. yunnanensis ‘Yunman’(YM). The active component 10DAB, growth, shoot biomass and 10DAB accumulation, as well as the N, P and K accumulation in different organs were measured under different fertilization methods and rates. The effects of different fertilization methods and fertilization amounts on 10DAB and nutrient accumulation of YM seedlings were studied. The results provide a theoretical and practical basis for precise regulation of nutrients and efficient cultivation of YM in seedling stage. The results showed that: (1) fertilization significantly increased the content of 10DAB in the branches and leaves of seedlings and promoted the growth and biomass accumulation of branches and leaves (P<0.05). Under the same nitrogen application rate, the branch and leaf biomass of exponential fertilization was significantly higher than that of average fertilization (P<0.05). The content of 10DAB in branches and leaves was higher in EF2 and EF3 treatments, and the growth and branch and leaf biomass were the largest in EF2 treatment. (2) The accumulation of 10DAB in exponential fertilization EF2 treatment was significantly higher than that in other treatments (P<0.05). The order was EF2 > EF1 > AF2 > EF3 > AF1 > EF4 > CK. Exponential fertilization EF2 was 30.61%-41.94% higher than average fertilization AF1 and 18.14%-25.00% higher than average fertilization AF2. (3) The effects of fertilization on the contents of N, P and K in all parts of seedlings reached a significant level (P<0.05). Under the same nitrogen application rate, the contents of N, P and K in each part of exponential fertilization were better than that of average fertilization. In exponential fertilization, the N content in roots and K content in each part increased with the increase of fertilization, while the N content in stems and leaves and P content in all parts, first increased and then decreased with the increase of fertilization. The distribution ratio of N, P and K showed the rule of leaf > root > stem. N and P, P and K in all parts of seedlings and N and K in roots and leaves showed significant (P<0.05) positive correlation, which was a synergistic relationship. (4) The accumulation of 10DAB in YM is the highest from September to October. At this time, the accumulation of 10DAB available for harvesting is the highest and the income is the largest. The study found that compared with conventional fertilization, exponential fertilization could increase the contents of 10DAB and the accumulation of nutrients in YM seedlings, and the amount of fertilizer applied was 1 600 mg·plant^-1.

Abstract:Populus euphratica Oliv. is a dioecious tree species for windbreak, sand fixation and soil and water conservation in desert riparian forest. In this study, male and female Populus euphratica plants with different diameter classes (8, 12, 16, 20 cm) were used as the research objects. Through analysis the contents and growth relationship of stoichiometric elements (C, N, P, K) in stems and leaves of the current year, the stoichiometric changes of different classes with developmental stages and the sex differences in allometric growth relationships were discussed. The results showed that: (1) the C content in the leaves of male and female plants of P. euphratica showed that the largediameter class (20 cm) was significantly higher than that of the small diameter class (8 cm), and the N content of leaves increased significantly with the increase of diameter class; Stem and leaf stoichiometry of male and female plants generally increased with the increase of diameter class, and C and N contents were significantly positively correlated with diameter class; With the increase of diameter class, the P content in leaves of female plants showed a downward trend, which was significantly negatively correlated with diameter class, while the P and K contents in stems of male and female plants showed an upward trend, and there was a significant positive correlation with diameter class. (2) The N content of the leaves of each diameter class and the P content of the 8, 12, and 20 cm diameter classes of the female plants were significantly higher than those of the male plants, and the C content of the current year stems of the 8, 16 and 20 diameter classes and the N and P contents of the stems of the 20 cm diameter classes were significantly higher than that of the corresponding male plants. (3) The slope indexes of C and N in the leaves of female plants are the largest in the 20 cm diameters class, while the slope indexes of male plants are the largest in the 12 cm diameters class. The changes of N and P in male and female plants are relatively stable in each development stage. At the same C content, the male stem can obtain more N content, and the female stem can obtain more P element under the same N. The research found that there are significant gender differences in the stoichiometric content and allometric growth relationship characteristics of stems and leaves between male and female Populus euphratica at different development stages. The mature female leaves need more stoichiometric characteristic content to meet the reproductive needs, which generally reflects the nutrient distribution strategy of their own growth and environmental adaptation.

Abstract:Rhizome root of bamboos is the major organ for absorbing nutrients and water. Its morphological and structural traits are closely related to the sensitivity of rhizome root to nutrient patches and ability of nutrients absorption. Two stand types of adjacent Pleioblastus amarus forest and mixed forest of P. amarusCunninghamia lanceolata were selected, and four habitats (central area of P. amarus and Cunninghamia lanceolata forest, boundary zone of P. amarus forest and mixed forest of P. amarusCunninghamia lanceolata) was established. We determined the morphological, structural traits and biomass of P. amarus rhizome roots in the four habitats, and analyzed the continuous variation among them to reveal the adaptation strategy of P. amarus to heterogeneous habitats. The results showed that: (1) in different habitats, P. amarus in boundary zone of P. amarus forest has a larger number of rhizome root nodes and root tips, and smaller root diameter. The specific root length and specific root area of the two boundary zones were all significantly higher than that of central area of P. amarus forest, while the rhizome root diameter of those two boundary zones changed on an opposite trend. (2) In direction from central area of P. amarus forest to central area of mixed forest, the biomass of rhizome root for P. amarus decreased gradually, but there were no significant differences on biomass of rhizome root between boundary zone of P. amarus forest and boundary zone of mixed forest. (3) The habitats had no significant effects on the allometric growth rate of the main morphological and structural traits of P. amarus, while displacement of the main morphological and structural traits of P. amarus from boundary zone forest increased significantly. There were significant differences on the morphological structure of rhizome root among different habitats. The morphological plasticity of rhizome root of P. amarus from boundary zone forest were higher, and rhizome root vigor and physiological function increased obviously. The results indicated that habitats affected main morphological and structural traits of rhizome root obviously, but only affected their allometric growth rate slightly. Rhizome root diameter played an important role in acquisition of heterogeneous resources. P. amarus tended to increase the area of rhizome root, but decrease its diameter to capture more resources in heterogeneous habitats.

Abstract:We selected 1 627 seed plants in Dehang Canyon of Hunan Province to explore the diversity composition basic rules of plant functional traits in the canyon habitat. Seven nutritional traits such as growth type, leaf type and leaf size and six reproductive traits such as sexual system, inflorescence type and fruit type were selected as the parameters for establishing the functional traits database of seed plants in this region. By statistical analysis of the database, we found that: (1) the nutritional traits of Dehang seed plants have the characteristics of both middle and south subtropical plant functional traits affected by the warm and humid environment of the canyon. The growth type was mostly perennial herbs, and the leaf was mainly mesophyllous and microphyllous, simple, papery, entire, undivided, alternate and hairless while the proportion of mesophyll was higher than that of microphyll. (2) The reproductive traits of Dehang seed plants were dominantly bisexuality, terminal and axillary infinite inflorescences, dry fruits and seeds spread by animals. There were more monoecious plants than dioecious, showing the adaptability to canyon habitat. The flowering period was concentrated from April to August, while the fruiting period was mainly from July to October. It is found that plant functional trait database plays an important role in exploring the composition rule of plant diversity in a specific environment, which is worthy of further researching and applying.

Abstract:Moss biocrusts are the critical active cover on the surface, with various ecological functions such as improving soil properties, fixing soil and water, sequestration of carbon and nitrogen, and microbiological community is the main component of Moss biocrusts to play its ecological function. To explore the wet area of lithophytic moss biocrusts microbial community composition and diversity characteristics, reveal its development and functional mechanism, our study focused on the lithophytic moss biocrust in five sampling sites of Niyu, Cheyu and Luoyu at the northern foot of the Qinling Mountains, used high throughput sequencing technology, analyzed the lithophytic moss biocrusts microbial community composition, abundance, diversity, and determined the relationship between nutrients and microbial community, to provide theoretical basis for the ecological restoration of bare rock wounds. The results show that: (1) the total nitrogen and organic matter contents of Qinling lithophytic moss biocrusts are between 4.16 to 8.26 g/kg and 89.44 to 131.05 g/kg, respectively, and the differences between the sampling site are significant; whole phosphorus and potassium was low, ranging from 0.88 to 1.21 g/kg and 13.50 to 18.10 g/kg, respectively. (2) Bacteria in the Qinling lithophytic moss biocrusts account for more than 80% of the microbial community, and the diversity of bacteria is much higher than that of fungi; Among them, the predominant bacterial flora are Proteobateria, Bateroidetes, Actinobacteria and Acidobacteria, and the dominant community of fungi are Ascomycota and Mortierellomycota. (3) The Redundancy analysis (RDA) shows that total potassium and organic matter significantly impact the structure of the predominant bacterial community. Proteobacteria and Bacteroidetes are suitable for living in the soil with high humidity and good nutrition; whole phosphorus and organic matter significantly influence the structure of the predominant fungal community, and the Mortierellomycota has more growth advantage in low phosphorus soil. It is found that bacteria are the main microbe of Qinling lithophytic moss biocrusts. Compared with the native situation in the arid region, Qinling lithophytic moss biocrusts showed significantly lower content of the Actinobacteria and Acidobacteria; for fungi, the relative abundance of Ascomycota and Basidiomycetes has significantly decreased, and significantly higher of Mortierellomycota. Organic matter is the most important nutrient factor affecting the composition of the microbial community in the moss biocrusts. The rich nutrients make the microbial community structure of lithophytic moss biocrusts in wet areas more complex and diverse and showed higher abundant species composition.

Abstract:Based on specimens and literature information, this study selected 19 environmental factors and 1 altitude factor, to simulate and predict the distribution pattern and potential suitable area changes of Medicago archiducisnicolai under the background of climate change. This research has reconstructed the geographical distribution of M. archiducisnicolai in five climate scenarios (the last interglacial, the last glacial maximum, the mid holocene century, current and future) by ArcGIS software and MaxEnt model. The prediction results showed that: (1) under the current climate, M. archiducisnicolai was mainly distributed in the intersection zone between the eastern edge of the QinghaiTibet Plateau and the Loess Plateau, including the eastern and southern parts of Qinghai, the central and southwestern parts of Gansu, the northwestern part of Sichuan, the southern part of Ningxia, the eastern part of Tibet and the western edge of Shaanxi. (2) High altitude, cold and dryness were the main environmental features of the M. archiducisnicolai appropriate areas. (3) It was relatively stable that the change in total area of the suitable areas in different climates, but the highly suitable areas were more sensitive to climate change. From the last interglacial period to the last glacial maximum, the highly suitable area moved eastward from the Hehuang valley in eastern Qinghai to the Taohe valley in central Gansu, and then moved westward to the Hehuang valley in the middle of the new century, but it did not move out of the Longzhong Basin. (4) Compared with the current climate, the suitable areas of the highly and moderately of M. archiducisnicolai were slightly increased in the 2070s, but the distribution pattern and potential suitable areas remained stable. The analysis showed that in the eastern margin of the QinghaiTibet Plateau, the basins and valleys created by the Kunlun Mountains, the Qilian Mountains and the Qinling Mountains provided a safe refuge in situ for M. archiducisnicolai, formed a unique and stable narrow distribution pattern, and the future climate change (2070s) would not pose a great threat to the plant.