Abstract:In this study, the fulllength cDNAs of two potato plant phytosulfokine receptor genes StPSKR1 and StPSKR2 were cloned from potato “Desiree”, and their bioinformatic analysis and localization analysis were performed. These will contribute to study the roles of PSK signal in potato growth, development and response to biotic stress. The results showed that: (1) the fulllength cDNA fragment of StPSKR1 and StPSKR2 genes were obtained by homologous cloning and PCR amplification, then cloned into pGWB5 vector. The protein sequence translated from the sequenced nucleotide results was consistent with that got from the database, indicating successful cloning of the StPSKR1 and StPSKR2 genes. (2) StPSKR1 is located on chromosome 1 of potato. The fulllength cDNA is 3 042 bp, encoding 1 013 amino acids. The relative molecular mass of predicted protein is 112.16 kD, the theoretical isoelectric point is 6.27. StPSKR2 is located on chromosome 7, and the fulllength cDNA is 3 135 bp. 1 044 amino acids with a relative molecular weight of 114.99 kD and a theoretical isoelectric point of 6.19. (3) Bioinformatic analysis showed that both StPSKR1 and StPSKR2 belonged to transmembrane proteins, including extracellular LRR regions, transmembrane regions and intracellular kinase regions. (4) Subcellular localization analysis showed that StPSKR1 and StPSKR2 localized on the cell membrane.

Abstract:Plants SWEET gene family is a kind of sugar transporter, which plays an important role in plant physiological activities and growth and development.In order to understand the information related to potato SWEET gene and explore its expression characteristics in different potato tissues and under biological and abiotic stress, we cloned the StSWEET5 gene from potato ‘Qingshu 9’ using homologous cloning technology(GenBank accession number is MN295671), whose CDS sequence length was 717 bp and encoded 238 amino acids.Phylogenetic tree analysis showed that the amino acid sequence similarity between the protein and that of tomato was the highest, reaching 97.06%. The results of qRTPCR showed that StSWEET5 gene was expressed in all tissues of potato (root, stem, leaf, flower, tuber and stolon), with the highest expression in flowers. StSWEET5 can be expressed in rhizomes and leaves under sugar stress, especially in roots (P<0.05). After 36 h induction of Phytophthora, the expression of Phytophthora in leaves was significantly uprated. It is speculated that StSWEET5 gene is involved in potato sugar stress and responds to late blight induction.

Abstract:In this study, in order to explore the molecular mechanism of oil metabolism in Camellia sinensis seed, we used transcriptome sequencing to analysis three different stages with young, formation and mature stage of seed development of ‘Tieguanyin’ cultivar. The results indicated that: (1) in total, 30 940 581 clean reads were obtained after transcriptome sequencing and assembly, 36 951 nonredundant Unigene sequences were obtained after data assembly, among which 28 476 Unigene could be functionally annotated. 11 201 Unigene (30.3%) were annotated into GO database. 17 172 Unigene were involved in 127 metabolic pathways by KEGG analysis. (2) 14 fatty acid metabolism pathways were selected by KEGG, and with the development of seed, most genes in fatty acid metabolism pathway were downregulated. The number of upregulated genes was the most in the alphalinolenic acid metabolic pathway (17 genes), while the number of downregulated genes was the most in the glycerolipid metabolic pathway (58 genes). More genes were upregulated than downregulated in the alphalinolenic acid metabolism pathway during young fruit stage of tea seeds. (3) A total of 409 differentially expressed genes (DEGs) related to synthesizing of tea seed fatty acid were identified, which were involved in 14 lipid regulation pathways. Some of the genes in the alphalinolenic acid metabolic pathway, like PLA2G16, DAD1, pldA, FabF and FabI, were upregulated significantly, and then the expression was downregulated subsequently. (4) Seven CsFAD genes and one CsACP gene were inspected by qRTPCR and their expression levels were consistent with transcriptome data. With the development of seeds, CsFAD7 and Δ6CsFAD showed downregulated and CsFAD2, CsFAD6 and Δ7CsFAD showed upregulated. CsFAD8, Δ8CsFAD and CsACP showed upregulated from young fruit stage to formation stage，and downregulated from formation stage to mature stage.

Abstract:In order to explore the mechanism of aquaporin (AQP) in response to drought stress in Artemisia ordosica, we amplified the AQP gene by RACE using A. ordosica in the Qaidam Basin of Qinghai Province. The fulllength gene of AQP was obtained and the structure of AQP protein was predicted and analyzed. At the same time, qRTPCR was used to analyze the expression patterns of AQP gene of A. ordosica in different degrees of drought stress and different tissues. The results showed that: (1) the 746 bp fragment 1 and the 534 bp fragment 2 of AQP gene were successfully cloned. The fulllength cDNA sequence was obtained after splicing. The total length of AQP gene of A. ordosica was 864 bp. (2) Subcellular localization indicated that the AQP gene of A. ordosica was located on the cell membrane. The homology alignment showed that the A. ordosica had high similarity with the AQP genes of plants such as Helianthus annuus, Lactuca sativa and Hevea brasiliensis. Structural prediction indicated that the AQP protein contained six transmembrane helix structures and was weak in hydrophilicity. In the protein secondary structure, αhelix and random coil were the main constituent elements. (3) According to qRTPCR analysis, the result showed that AQP gene of A. ordosica showed regular changes with the increase of drought stress. The expression of AQP gene was upregulated in roots, stems and leaves, the highest was in leaves. So the above results indicated that the AQP gene had distinct structural characteristics and expression patterns to adapt to drought stress. This study provided the foundation for further characterizing the mechanism of A. ordosica drought resistance.

Abstract:In order to explore anthocyanin synthsis regulator genes in Gynura bicolor, we sequenced the transcriptomes of G. bicolor including leaf and flower in control by Illumina HiSeq 2 500 platform. Then, 8 kinds of synthases such as CHS, CHI, F3H, F3′H, F3′5′H, DFR, ANS, 3GT and 3 kinds of transcription factors such as MYB, bHLH and WD40 were retrieved. At the same time, 8 differential expressed genes were identified by the RTPCR. The results showed that: (1) There were 72 unigenes related to anthocyanin synthases, in which 12 differential expressed genes including 1 downregulated F3′H, 2 downregulated 3GTs, 5 downregulated F3Hs and 4 upregulated F3Hs. (2) There were 238 MYBs, 113 bHLHs and 219 WD40s. The differential expressed genes in these 3 kinds of transcription factors were 22, 16 and 7, respectively. (3) According to transcriptome sequencing, the downexpression trend of these 8 anthocyanin synthesis regulator genes agreed with the testing by the RTPCR. But the trend multiples of these differentially expressed genes by these 2 kinds of approaches were different. So this study concluded that there are many anthocyanin synthesis regulator genes in G. bicolor including leaf and flower, but only a few of these genes are significantly different. At the same time, the regulation of transcription factors is more complex than that of synthases.

Abstract:In this study, the whole chloroplast genome sequence of Elaeagnus angustifolia Linn was assembled by sequencing total genome DNA with the second generation sequencing. Young leaves of E. angustifolia were collected from shoots of two wild individuals under hydroponic growth in greenhouse , and total DNA of the two individuals were extracted separately by CTAB method for two repeats of the chloroplast genome. The codon usage bias of proteincoding genes and its causes were analyzed in detail. The results of this study are of great significance for future chloroplast genetic engineering and molecular phylogenetic researches in E.angustifolia. The results show: (1) the full chloroplast genome sequence of E. angustifolia was a circular molecule of 150 546 bp in length with a typical quadripartite structure, including a pair of inverted repeats (IRA and IRB) of 25 494 bp that were separated by large and small single copy regions (LSC and SSC) of 81 113 bp and 18 445 bp, respectively. A total of 132 predicted genes, including 86 proteincoding genes, 39 tRNA genes and 8 rRNA genes, were identified. (2) The GC content of the third nucleotide in all proteincoding genes was 28.47%, which was significantly lower than that GC₂ and GC₁, indicating that the E. angustifolia chloroplast gene codon has a preference for the end of the A or T base, and eight optimal codons, UCU, CCU, UGU, GCU, CUU, GAU, UCA and UAA were determined. (3) We analyzed the codon bias of the chloroplast genomic protein coding sequence of E. angustifolia. Corresponding analysis of RSCU indicated that mutations, selection and other factors may all affect the codon usage pattern, and the sequence difference caused by natural selection is more significant than the mutation to codon usage bias. Effective Number of Codon plot (ENCplot) analysis and Parity rule 2 plot (PR2plot) analysis indicated that the bias of codons in the chloroplast genome of E. angustifolia was mainly influenced by selection, although mutation may also have played a role. (4) Cluster tree based on the Relative Synonymous Codon Usage (RSCU) values of chloroplast genes from seven species in Elaeagnaceae is basically consistent with phylogenetic tree based on chloroplast whole genome sequences, which illustrated that codon usage bias pattern in the chloroplast genomes of species in Elaeagnaceae was related to the phylogenetic relationship of these species.

Abstract:To explore the relationship and biogeographic distribution pattern of A. macrostemon in different areas of Southwest China, we compared and analyzed 27 nrDNA ITS sequences of A. macrostemon, of which 21 were newly generated and 6 from GenBank. The results showed: (1) the sequence length of the A. macrostemon Bunge varied from 607-638 bp and the GC content of 48%-52%, with an average 50%. (2) A. macrostemon is monophyletic basing on Bayesian inference and Maximumparsimony analysis. (3) Phylogenetic analysis indicated that the 27 populations are generally divided into group a and group b. Among them, Jiange County, Sichuan, Wixi County, Chongqing, Dejiang County, Guizhou and Qiubei County, Yunnan, located in the east of Southwest China, are clustered into group a; Wenchuan, Shimian, Jiangyou of Sichuan Province and Hutiaoxia, Kunming, Sanba of Yunnan Province located in the west of Southwest China belongs to group b. The results suggested that nrDNA ITS sequence could identify the relationship of A. macrostemon in different regions.

Abstract:In this study, we systematically investigated the ultrastructure of the phloem and surrounding parenchyma cells using transmission electron microscopy during the development process of Xanthoceras sorbifolium Bunge fruit, to understand the unloading pathway and mechanism during the fruit development. The results showed: (1) during the fruit development process, the cell cavity of the sieve element (SE) was empty and few organelles exited, but there were some vesiclelike and microfibrillike structures in SE. With increase of cytoplasm density and organelles abundance, the degree of vacuolization in companion cell (CC) varied, and most of them had multiple small vacuoles; Phloem parenchyma cell (PP) had large central vacuoles, and vesicle transport occurred in the middle stage of development. They were rich in organelles such as mitochondria, golgi bodies and endoplasmic reticulum, which degraded at the later stage of development. This indicated that the metabolism and substances transport in fruit decreased gradually with the fruit development. (2) During the development of fruit, there were always some plasmodesmata between SE and CC, and lots of plasmodesmata between CC. However, only a certain number of plasmodesmata existed between the SECC complex and PP at the early and late stage of fruit development, but almost no plasmodesmata existed at the middle stage of fruit development. Based on the above results, we concluded that the unloading pathway of assimilate changed from symplastic to apoplastic and then to symplastic during the fruit development.

Abstract:In this study, more than 100 samples of Rhizocarpon in Xinjiang were used as materials to study the species diversity of Rhizocarpon in Xinjiang by morphological and anatomical observation, chemical composition analysis and molecular identification. The results obtained from this study are as follows: (1) seven species of Rhizocarpon distributed in Xinjiang were identified, including one newly recorded species named R. atroflavescens, and six common species, namely, R. badioatrum, R. disporum, R. geminatum, R. geographicum, R. grande and R. superficiale. (2) A subspecies search table for 22 kinds of Rhizocarpon in Xinjiang was compiled. (3) The phylogenetic analysis of Rhizocarpon in the genus Caryopsis showed that the results of molecular identification were consistent with those of morphological and anatomical characteristics, and the new recorded species in China was more clearly identified as pale yellow Caryopsis. (4) The regional distribution and elevation distribution of 22 species of Rhizocarpon in Xinjiang were analyzed. The results show that the 22 species of Rhizocarpon are distributed all over the world, with Asia being the most abundant. The 22 species of Rhizocarpon are distributed from low to high altitudes, but not distributed evenly, more species distributed in the high altitude range.

Abstract:The ‘Xinchun No.4’ cucumber was used as the test material in this experiment. Meanwhile, the effects of exogenous 4 mmol·L^-1Na₂SiO₃·9H₂O on the cucumber seed germination and growth, membrane lipid peroxidation level, antioxidant enzyme activities and starch transformation were studied under continuous substrate leach solution (subtract∶water = 1∶6) for revealing the alleviating effect of exogenous silicon on cucumber seed germination inhibited by continuous cropping matrix extract and its physiological and biochemical mechanisms, moreover, providing theoretical basis for solving the problem of continuous cropping obstacles in cucumber substrate cultivation in production. The results showed that: (1) continuous substrate leach solution significantly inhibited the germination of cucumber seeds by increasing malondialdehyde (MDA) and proline (Pro) contents, decreasing the activities of antioxidant enzymes and starch hydrolase activities, and enhancing starch content during seed germination. Also, the leach solution decreased soluble sugar content, and the gene expression levels of AMY and BMY were significantly downregulated. (2) Application of exogenous silicon could effectively alleviate the inhibition of cucumber seed germination by reducing MDA and Pro contents, enhancing activities of antioxidant enzymes and starch hydrolase, elevating soluble sugar content, and upregulating the expression of AMY and BMY genes. The research showed that 1∶6 concentration of continuous substrate leach solution can inhibit the germination of cucumber seeds, led to block starch transformation, and gene expression downregulation；However, exogenous addition of 4 mmol·L^-1 Na₂SiO₃·9H₂O could accelerate the rate ofstarch conversion and maintain the normal physiological function during germination of cucumber seeds and to alleviate the negative effects caused by the continuous substrate leach solution on cucumber seed germination.

Abstract:Hydrogen sulfide (H₂S) is a novel endogenous gaseous signal molecule that regulates plant stress resistance. To investigate the alleviation effect and mechanism of exogenous hydrogen sulfide (H₂S) on tobacco seedlings growth under drought stress. This study adopted the method of nutrient solution hydroponics and used 15% polyethylene glycol (PEG6000) to simulate drought stress. Fluecured tobacco (Nicotiana tabacum cv. ‘Yuyan No.6’) was tested for their response following foliarspraying with sodium hydrosulfide (NaHS) at concentrations of 0, 0.1, 0.2 and 0.4 mmol·L^-1. Parameters measured included seedling growth, active oxygen metabolism, antioxidant enzyme activity, chlorophyll content and photosynthetic fluorescence characteristics. The results showed that： (1) tobacco seedling growth was significantly inhibited under drought stress.(2) Exogenous H₂S treatments significantly enhanced both shoot and root fresh weight, increased the total root length, total root surface area, average root diameter and root tip number of tobacco seedlings, enhanced chlorophyll relative content (SPAD), net photosynthetic rate (P_n), transpiration rate (T_r), stomatal conductance (G_s), maximal PSⅡ quantum yield (F_v/F_m), PSⅡ actual photochemical efficiency(Φ_PSⅡ) and photochemical quenching coefficient (qP), and reduced intercellular carbon dioxide concentration (C_i) and nonphotochemical quenching coefficient (NPQ), enhanced the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), and decreased malondialdehyde (MDA) content and superoxide anion (O₂^-·) generation rate under drought stress. Foliar application with 0.20 mmol·L^-1 NaHS produced the largest growth promotion effects and drought stress alleviation.(3) Compared with drought stress alone, 0.20 mmol·L^-1 NaHS increased shoot and root fresh weight of tobacco seedling by 41.82% and 44.83%, enhanced SPAD, P_n, F_v/F_m, Φ_PSⅡ and qP by 62.88%, 246.96%, 8.43%, 23.71% and 10.84%, decreased C_i and NPQ by 25.79% and 22.68% enhanced the activities of SOD, POD and CAT by 50.67%, 140.59% and 71.68%, reduced MDA content and O₂^-· generation rate by 40.08% and 47.58%, respectively. These results indicated that exogenous H₂S positively stimulated tobacco seedlings to capture and convert solar energy, thus promoting seeding photosynthesis and growth, and also enhanced the adaptability of seedlings to drought stress by improving antioxidant capacity and reducing oxidative damage.

Abstract:In this study, 2yearold Malus halliana Koehne were treated under salt stress (NaCl), saltalkali mixed stress (NaCl+NaHCO₃, 1∶1), alkali stress (NaHCO₃) and water as the control (CK). The changes of pigment content, photosynthetic parameters, chlorophyll fluorescence parameters, relative conductivity and osmotic adjustment substance content of Malus halliana Koehne leaves at different time points were determined by pot experiment to explore the physiological response characteristics of M. halliana Koehne under different salinealkali stress. The results suggested that: (1) under three salinealkali stress conditions, the synthesis of photosynthetic pigments (chlorophyll a, b and carotenoids) in leaves of M. halliana Koehne was inhibited with the prolongation of stress time, and the decrease was most obvious under alkali stress. After 40 days of stress, Chl a, Chl b and Car decreased by 67.18%, 68.90% and 64.67%, respectively. (2) The net photosynthetic rate (P_n), stomatal conductance (G_s) and transpiration rate (T_r) of M. halliana Koehne leaves were inhibited under three salinealkali stresses and significantly lower than CK, while the intercellular CO₂ concentration (C_i) under alkali and salinealkali treatments increased by 137.13% and 77.66% respectively after 20 d of stress, and decreased by 56.82% and 51.89% respectively after 40 d of stress. (3) With the extension of stress time, the actual photochemistry efficiency (Φ_PSⅡ), maximum fluorescence (F_m), photochemical quenching coefficient (qP) and maximum photochemical efficiency (F_v/F_m) of M. halliana Koehne leaves were inhibited under three salinealkali stresses. However, the initial fluorescence (F₀) and the nonphotochemical quenching coefficient (qN) of salt treatment and saltalkali mixed treatment showed an increasing trend under alkali stress, and increased by 60.98%, 90.70%, 99.15% respectively after 40 days of stress compared with CK. (4) Compared with CK, the relative electrical conductivity (REC) of leaves in salt, alkali and saltalkali treatments increased by 9.39%, 35.07% and 29.32% respectively after 40 days of stress. At the same time, soluble sugar (SS), proline (Pro), organic acid (OA) of leaves were significantly higher than that of CK after 40 days of stress, and OA was more sensitive to saltalkali mixed treatment. The amount was significantly higher than that of salt treatment and alkali treatment. (5) The growth and photosynthesis of M. halliana Koehne under three stresses were inhibited by alkali treatment > saltalkali mixed treatment > Salt treatment. It was found that the photosynthesis of M. halliana Koehne was significantly inhibited by three salinealkali stresses, and the effect of alkali stress was greater, but it could cope with the stress by osmotic regulators, effectively alleviate the damage of salinealkali stress and enhance its saltalkali tolerance.

Abstract:In this study, the effects of methyl jasmonate (MeJA) with various concentrations (0,0.5, 1.0, 5.0, 10.0, 25.0 μmol·L^-1) on seed germination and seedling growth and antioxidant system of coreopsis has been explored. Seeds were germinated on filter paper bedding and leaf spray of potted seedlings. The results showed that the growth of coreopsis was severely inhibited when the cadmium ion concentration is 100 μmol·L^-1. The application of MeJA (1.0-5.0 μmol·L^-1) promoted the germination and increase the chlorophyll content of coreopsis seedlings, promoted leaf dry matter accumulation and increased relative leaf water content, increased the activities of antioxidase, increased the contents of oxidized glutathione and the rate of oxidized glutathione/reduced glutathione values, reduced the contents of malondialdehyde and proline. The low concentration of MeJA could effectively alleviate the damage of cadmium stress. However, high concentration of MeJA (above 10 μmol·L^-1) exhibited inhibitory effects on the metabolism of coreopsis seedlings. Overall, appropriate concentration of exogenous MeJA could promote the growth and cadmium tolerance of coreopsis, through decreasing osmotic adjustment substance contents, enhancing antioxidant enzyme activities, increasing GSH content and adjusting GSH/GSSG ratio.

Abstract:To study the effect of selenium on the growth of ginseng and cultivate seleniumenriched Talinum paniculatum, we conducted pot experiment to determine the changes of T. paniculatum growth, leaf photosynthetic pigment content, physiological characteristics and selenium accumulation with selenium application (0, 2.5, 5, 10, 20 mg/kg). The results showed that: (1) selenium application had the effect of “low promotion and high inhibition” on the growth of T. paniculatum. The plant height, stem diameter, root length, number of branches and biomass of T. paniculatum increased first and then decreased. (2) Selenium application can increase the content of photosynthetic pigment in T. paniculatum leaves, and high concentration selenium (≥10 mg/kg) has significant effects on photosynthetic pigment content in T. paniculatum leaves. (3) The SOD and POD activities of T. paniculatum leaves were the highest at the concentration of 2.5 mg/kg (P<0.05), and the highest at CAT activity was 5 mg/kg (P<0.05). With the increase of selenium concentration, the content of vitamin C in the leaves of T. paniculatum increased gradually, the content of soluble protein increased first and then decreased, and the content of soluble sugar decreased. (4) The distribution of selenium in T. paniculatum was: root>leaf>stem, and it increased with the increase of selenium application; T. paniculatum root was the main part of selenium accumulation. According to the study, the concentration of selenium is 5 mg/kg, which is the best concentration for cultivating seleniumenriched T. paniculatum.

Abstract:The experiment designed four kinds of soil compaction treatment ［soil bulk density of 1.2 (CK₁), 1.3, 1.4, 1.5 g·cm^-3］, and four inoculation treatments ［Fm, Ri, Fm+Ri, and noninoculation (CK₂)］ with inoculating two kinds of arbuscular mycorrhizal fungi (including Funneliformis mosseae，F_m and Rhizophagus intraradices,Ri) before compaction treatment, and a total of 16 treatments. We analyzed the effects of different treatments on the physiological and ecological indexes of Festuca elata variety ‘Ai Rui 3’, and provided a theoretical basis for the application of AMF in compacted soil. The results showed that: (1) the mycorrhizal infection rate and mycelial density of the roots of tall fescue decreased gradually with the increase of soil bulk density. Compared with CK₁, the infection rate of roots of high fescue roots inoculated with Fm, Ri and Fm+Ri under treatment with soil bulk density of 1.5 g·cm^-3 was significantly reduced by 27.8%, 39.8% and 30.0%, respectively. The mycelial density decreased significantly by 43.8%, 42.1% and 43.8%, respectively. Moreover, under 1.5 g·cm^-3 soil bulk density, the mycorrhizal infection rate and mycelial density of Fm+Ri treatment increased by 17.3% and 25.2%, respectively, which was 53.0% and 36.3% higher than that of single inoculation, respectively. (2) Inoculation with AMF can effectively increase the plant height, tiller number and dry matter quality of tall fescue plants under soil compaction stress, and significantly improve the tolerance of tall fescue. Plant height, tiller number and dry matter quality of Fm+Ri treatment were significantly increased by 36.1%, 39.5% and 144.0%, respectively, under 1.5 g·cm^-3 soil bulk density compared with CK₂. (3) Inoculation with AMF significantly increased the root activity and catalase (CAT) activity of tall fescue under soil compaction stress. The root vigor and CAT activity of Fm+Ri inoculated with 1.4 g·cm^-3 soil bulk density were 1.4 times and 1.5 times than that of CK₂, respectively. (4) Inoculation with AMF can significantly increase the contents of chlorophyll a, b and total chlorophyll in tall fescue under soil compaction stress. Inoculation with Fm+Ri treatment in the soil bulk density of 1.5 g·cm^-3 was 43.1%, 100.0% and 59.3% higher than that of the CK₂. (5) Inoculation with AMF significantly increased the net photosynthetic rate (P_n), transpiration rate (T_r) and stomatal conductance (G_s) of tall fescue under soil compaction stress, and significantly decreased the intercellular CO₂ concentration (C_i) of leaves. Inoculation with Fm+Ri treatment was 52.5%, 33.3%, 181.1% and -32.9% higher than that of the CK₂ under the soil bulk density of 1.5 g·cm^-3. In summary, soil compaction stress significantly inhibited the infection of AMF, and coinoculation significantly promoted the infection of AMF on roots, and the effect of coinoculation with Fm+Ri was significantly better than single inoculation. AMF can enhance its own resistance to soil compaction by enhancing the activity of tall fescue roots, reducing the damage caused by oxidative stress, increasing plant chlorophyll content and photosynthesis.

Abstract:Based on a 12year simulated warming and nitrogen(N)addition experiment, we explored the effects of warming and N addition on nutrient resorption for two common species, C₃ plant Convolvulus ammannii and C₄ plant Kochia prostrata, in 2016 with 52% above the longterm mean precipitation and in 2017 with 16% below the longterm mean. Plant N and phosphorus(P)contents, and resorption efficiencies were measured and analyzed. The results showed that: (1) in the wet year (2016), warming led to increases of 14.32% in green leaf N, 25.45% in senesced leaf N, 17.97% in green leaf P, 46.47% in senesced leaf P, and the N and P resorption efficiency significantly decreased by 9.41% and 16.99% (P < 0.05). N addition enhanced N contents in green and senesced leaves by 17.32% and 25.62%, and P contents in green and senesced leaves by 20.21% and 51.41%, but it significantly reduced N and P resorption efficiency by 9.33% and 18.89%(P < 0.05). Combined warming and N addition increased leaf N and P contents, and decreased resorption efficiency. (2) In the dry year (2017), warming and N addition, had no significant effect on these plant nutrient characteristics. (3) Significant differences in leaf N and P contents were found between the two species, and those of resorption efficiency were not observed. (4) Regression analysis indicated that N and P concentrations in plant leaves increased with soil N, P and water availability, while the resorption efficiency of plant N and P decreased with soil N, P and water availability. Research showed that the responses of nutrient resorption to warming and N addition could be mediated by variations of natural precipitation in a desert steppe.

Abstract:The project conducted a potculture method to study the effect of Cupressus funebris root exudates on the growth of Koelreuteria paniculata fine roots in mixed forests. Four experiment groups of G1, G2, G4 and G8 were set up and separately added the potted seedlings of K. paniculata, followed by treatment with root exudates of 1, 2, 4, and 8 cypresses respectively, which investigated the effects of that root exudates on fineroot morphology, N and P contents in orders 1-5 roots. The results showed that: (1) fineroot diameter increased with root order increasing. Root exudates significantly reduced fineroot diameter in orders 1-2. Specific root length and specific root surface area decreased while root order increasing. Root exudates significantly increased specific root length and specific root surface area in orders 1-2. With the increasing concentration of root exudates, specific root length and specific root surface area increased firstly, while the diameter decreased firstly, followed by all of them tended to be stable. (2) Contents of N and P decreased with the increase of root order, but the change of N/P in root order was not obvious; root exudates significantly increased N and P contents in fineroot orders 1-2, but decreased N/P in orders 1-5; with the growing concentration of root exudates, fineroot P content increased, N/P decreased, and N content increased primarily and then remained no change. (3) Contents of N and P in fine roots were remarkably correlated with the morphological characteristics. Root exudates could improve the availability of soil nutrients, thereby alleviating the symptoms of P deficiency in plants. Fine roots could enhance nutrient use efficiency through adjusting their morphology. Meanwhile, root exudates mainly affected morphology and contents of N and P in fineroot orders 1-2. The results indicated that root exudates from 4 strains of C. funebris were more beneficial to the growth of K. paniculata.

Abstract:In this study we investigated the effects of different temperatures and initial density ratios of Navicula pelliculosa and Microcystis aeruginosa on their growth competition. Different temperature gradients (10, 15, 20, 25, 30 and 35 ℃) and different initial density ratios (1∶10, 1∶1, and 10∶1) were used. The results showed that: (1) in the xenicculture systems, N. pelliculosa and M. aeruginosa reached the maximum growth rates at 20-25 ℃ and 35 ℃, respectively, with their maximum biomass being 3.883×10⁵ and 4.813×10⁶ cells/mL respectively. (2) In the coculture systems, temperature and the initial density ratios both significantly influenced the competition between N. pelliculosa and M. aeruginosa. Higher initial density of N. pelliculosa resulted in greater advantage on their competitive capacity, and the growth inhibition effect of N. pelliculosa on M. aeruginosa was most obvious with the initial density ratio of 10∶1 when at 25 ℃. (3) According to the LotkaVolterra model, it can be inferred that M. aeruginosa preponderated at high temperature (30-35 ℃). At low temperature (10-20 ℃), M. aeruginosa and N. pelliculosa coexist stably when their initial density ratio was 1∶10. N. pelliculosa dominated when the initial density ratio of N. pelliculosa to M. aeruginosa was 1∶1 or 10∶1.When N. pelliculosa was reached the temperature of 25 ℃ and the initial density ratio was 10∶1, M. aeruginosa and N. pelliculosa were unstably coexist in the coculture system.

Abstract:This paper characterized the variation in leaf functional traits of woody plants in a subtropical evergreen and deciduous broadleaved mixed forest, and the response of community functional diversity to altitude gradient, which was located in the altitudes from 1 200 and 1 700 m in Xingdoushan National Nature Reserve in southwest Hubei. The leaf area (LA), specific leaf area (SLA), leaf dry matter content (LDMC), leaf thickness (LT) and leaf nitrogen content (LNC) of woody plants in the forest community, and the variation characteristics of six leaf functional traits in leaf phosphorus content (LPC) were analyzed. The response of leaf functional traits and functional diversity of woody plants to altitude changes was also analyzed. The results showed that: (1) the average leaf area, specific leaf area, leaf dry matter content, leaf thickness, leaf nitrogen content and leaf phosphorus content of woody plants in the Xingdoushan Nature Reserve were 151.49 cm², 247.98 cm²/g and 34.08%, 0.21 mm, 16.59 mg/g and 0.04 mg/g, respectively, and their variation ranges were 206.96%, 57.00%, 28.15%, 52.38%, 24.83% and 76.92%. (2) Among the four factors of the family, leaf habit, life form and tree height category, the family had the greatest influence on the six leaf functional traits, followed by leaf habit. (3) The altitude had a significant effect on leaf area, leaf dry matter content and leaf phosphorus content (P<0.001). However, its effect on leaf area, leaf thickness and leaf nitrogen content were not significant (P>0.05). (4) The biological activity, functional richness, functional divergence and functional dispersion of the community were significantly different on different altitude gradients (P<0.05), only the functional evenness was not significantly different in the altitude gradient (P>0.05).

Abstract:In this paper, morphology,anatomy,lichen chemistry and molecular biology methods were selected to study the specimens of Lecidea from Xinjiang, and morphological characters, the secondary metabolites, and the phylogenetic tree of ITS were studied.The results showed that: (1) there were three species of Lecidea new to China which were Lecidea fuscoatrina Hertel & Leuckert, L. perlatolica Hertel & Leuckert and L. polypycnidophora U. Rupr. & Türk, and photos of the thallus, apothecia, asci and ascospores of them were provided. (2) The taxonomic status of the three species and the related species were studied and discussed through the ITS phylogeny in detail. The three species and the related species respectively formed three clades and were used to identify the species having subtle morphological differences.

Abstract:The genus Amentotaxus Pilg. and its species Amentotaxus argotaenia (Hance) Pilg. are reported for the first time as a new record from Shaanxi Province, China. A brief description and photos are provided. The voucher specimens were deposited in Herbarium of Shaanxi University of Technology (HZTC).

Abstract:Many plant species have adapted well to the complex environment through different strategies, one of which is the production of additional secondary metabolites. Terpenoids are one kind of the most complex plant secondary metabolites, existing in almost all plants with many crucial functions. Some of them have significant pharmacological activity, such as immunoregulation, antitumor, lipidlowering and hepatoprotective. In order to explore the fundamentalrules of environmental factors on the plant terpenoids biosynthesis, this review summarizes the factors of terpenoids biosynthesis in plants in recent years, including environment temperature, ultraviolet radiation, light, water, ozone and developmental phases.