Abstract:In order to explore the functions of histone lysine methyltransferase (HKMT) gene in Lycoris aurea, we cloned a histone lysine methyltransferase gene LaSUVH1 using the RTPCR method based on previous transcriptome sequencing data. The coding sequences (CDs) of LaSUVH1 gene is 2007 bp in length, encoding a deduced polypeptide of 668 amino acids. LaSUVH1 is a stable hydrophilic protein without signal peptide, and had no transmembrane structure. It had SET {Suppressor of Variegation 3-9 ［SU(VAR)3-9］, Enhancer of Zeste ［E(Z)］, and Trithorax (TRX)}, YDG (named for three conserved amino acids)/SRA (SET and RING fingerassociated), PreSET, and PostSET conserved domains. Multiple sequence alignment and phylogenetic tree analysis showed that the deduced protein LaSUVH1 shares higher identity with Asparagus officinalis AoSUVH1like protein. Additionally, quantitative realtime PCR (qRTPCR) analysis indicated that LaSUVH1 was ubiquitously expressed in different tissues, and had the highest expression level in leaf. By hygromycin screening, three transgenic Arabidopsis thaliana lines with antisenseoverexpression of LaSUVH1 gene were obtained. Further functional analysis showed that antisenseoverexpression of LaSUVH1 gene promoted lateral root formation, reduced the tolerance to NaCl stress and increased the sensitivity of seed germination to abscisic acid (ABA) in Arabidopsis, suggesting LaSUVH1 functioning in salt stress response might be involved in ABAdependent signaling pathway.

Abstract:RNAi expression vector of cycloartenol synthase gene (PjCAS) from Panax japonicus was constructed by Gateway technology in this study, and Agrobacteriummediated transformation was used to realize RNAi of PjCAS in P. japonicus cells successfully. Realtime quantitative PCR was used to analyze the expression of key enzyme genes involved in the biosynthetic pathway of P. japonicus saponins (PJS), the changes of saponins and phytosterols in transgenic cells were also determined, and the regulation effect of PjCAS on the synthesis of PJS was discussed. The results showed that: (1) the RNAi fragment of PjCAS was amplified, and the PjCAS RNAi vector pHellsgatePjCAS was successfully constructed. (2) Six positive transgenic cell lines with PjCAS interferance were obtained by Agrobacterium transformation. (3) Compared with the ordinary cell line, the expression of PjCAS in transgenic cell lines was approximately decreased by 85%, and the highest expression levels of key enzyme genes PjDS and PjAS directly related to saponins synthesis were upregulated by 90% and 150%, respectively. (4) The contents of six monomeric saponin in the transgenic cell lines were significantly higher than that of control, among them, the average contents of dammaranetype monomeric saponin Re, Rb1, Rd and oleananetype monomeric saponin R0, IV, IVa were higher than that of the normal P. japonicus cells, increased by 28%, 49%, 40%, 36%, 59%, and 50%, respectively. The results indicated that the change of PJS content is indirectly regulated by PjCAS gene. (5) The phytosterol content in six transgenic cell lines decreased by 53%-73% than that in control group. Studies have found that silencing PjCAS gene can significantly upregulate the expression of key enzyme genes PjDS and PjAS related to the synthesis of PJS, and increase the content of monomeric saponin in the cell lines with PjCAS, thus promote the significant increase in the synthesis of PJS. The results prove that the metabolic flux of the branch of phytosterol synthesis could be decreased by inhibiting the expression of PjCAS, the key gene in the biosynthetic pathway of phytosterols. As a result of it, more metabolic flux flowed towards the synthesis of PJS and the biosynthsis of PJS was promoted.

Abstract:According to the data of Sol Genomic Network, we obtained the fulllength of SlWRKY6 (Solyc02g080890) from cultivated tomato variety M82 by RTPCR and verified its biological function by prokaryotic expression. The results showed that: (1) an open reading frame (ORF) of SlWRKY6 was obtained from Solanum lycopersicum, which is 1 653 bp long and encodes 550 putative amino acids with a WRKYGQK conserved domain and C₂H₂ zinc finger domain, belonging to IIb subgroup. The upstream of the SlWRKY6 promoter contains several hormone response elements and abiotic stress response elements. (2) Phylogenetic tree analysis showed that SlWRKY6 shared a high degree of sequence similarity with SpWRKY31X1 (NP_001352691.1) from Solanum pennellii and localized to the nucleus. (3) qRTPCR results showed that the pattern of SlWRKY6 was highly expressed in leaves and also induced by salt and drought stress. (4) SDSPAGE and Western blot analysis showed that the molecular weight of SlWRKY6 was approximately 66 kDa. (5) Prokaryotic expression analysis showed that the growth rate of recombinant E. coli BL21∷pET30aSlWRKY6 was significantly lower than that of the control E. coli BL21∷pET30a under different concentrations of salt (NaCl) or drought (mannitol) stress, especially under 400 mmol/L NaCl and 800 mmol/L mannitol stress. In addition, the drip plate test showed that SlWRKY6 gene could enhance the tolerance of E. coil to salt, drought and ABA stresses. Taken together, the transcription factor SlWRKY6 might respond to abiotic stress by participating in the ABA pathway.

Abstract:SWEET (sugar will eventually be exported transporters) protein participates in the loading of phloem sugars. In this study, 9 BeSWEET sequences were screened based on the transcriptome library of Bambusa emeiensis and analyzed by bioinformatics; Genes of BeSWEET42 and BeSWEET1a2 among the 9 BeSWEET sequences were cloned with the cDNA of the stem and young leaf of B. emeiensis. Real time quantitative expression analysis (qRTPCR) was used to analyze its expression levels in mesophyll, veins, roots, stems and the expression changes of BeSWEET gene induced by exogenous sugar. The results showed that: (1) phylogenetic tree analysis showed that 9 BeSWEET sequences were divided into four clades. BeSWEET42 which has two MtN3 conserved domains is homologous to rice SWEET4, clustered into Clade Ⅱ. BeSWEET1a2 is homologous to rice SWEET1a and SWEET1b, and clustered into Clade Ⅰ. (2) Sequence analysis showed that BeSWEET42 and BeSWEET1a2 encode 256 and 222 amino acids, respectively, and have 7 and 5 transmembrane domains, respectively. (3) The prediction of subcellular localization indicates that both genes are located in the plasma membrane. (4) qRTPCR analysis shows that BeSWEET42 and BeSWEET1a2 are mainly expressed in roots and veins, respectively. It is speculated that they may cooperate in the transport of carbohydrates from source to sink. (5) Both BeSWEET42 and BeSWEET1a2 were significantly upregulated under the induction of hexose, showing a preference for hexose. Our study provides the insight for understanding of biological functions of B. emeiensis BeSWEET proteins in regulating sugar transport.

Abstract:In order to study the molecular adaptation mechanism of the alpine plant Saussia medusa to high ultraviolet radiation, we cloned the cDNA and promoter sequences of anthocyaninrelated SmMYB1 gene by RTPCR combined with RACE methods and hiTAIL PCR. The results show that: (1) the length of SmMYB1 cDNA (GenBank: MT188353) is 1 011 bp encoding 269 amino acids, and the sequence of gDNA contains two introns and three extrons. (2) Bioinformatics analysis show SmMYB1 protein has more high similarity with MYB in Asteraceae contained the ［DE］Lx(2)［RK］ x(3)Lx(6)Lx(3)R and ANDV motifs, and belongs to the sixth subfamily of Arabidopsis thaliana. The length of SmMYB1 promoter (GenBank: MT188354) is 1 407 bp, which contains many light responsive elements. (3) qRTPCR shows that SmMYB1 gene is expressed in roots, stems, leaves and flowers, and the highest expression emerges in the flowers. Under ultraviolet radiation stress, the expression of SmMYB1 reaches the highest at 4 h, and then decreases gradually. It is speculated that SmMYB1 can regulate anthocyanin synthesis and is involved in the UV responsive pathway in S. medusa.

Abstract:HAM subfamily genes of the GRAS family are important regulators for maintaining the undifferentiated state of shoot apical meristem (SAM), and affect the process of floral transition process in plants. In this study, based on the homologous sequences of HAM subfamily genes from a transcriptome dataset, three HAMlike genes were cloned from Chrysanthemum lavandulifolium by RTPCR technology. Sequence analysis showed that the open reading frames (ORF) of the three genes were 1 845, 1 479 and 1 881 bp in length, encoding 614, 492 and 626 amino acids, respectively. Blastp analysis showed that the coding products of the three genes contain typical structures of HAM subfamily, and show high identity with the SCL6 protein of Artemisia annua, which reach up to 94.39%, 91.90%, and 94.27%, respectively. Further analysis showed that amino acid sequences translated by the three genes had the closest evolutionary relationship to SCL6 in all Arabidopsis GRAS family members, so they were named as ClSCL6a, ClSCL6b, ClSCL6c, respectively. Fluorescence quantitative analysis showed that the three genes were highest expressed in the stems of C. lavandulifolium, and generally with low expression level in roots and flowers. In floral organs of different development stages, all the three ClSCL6 genes were expressed. ClSCL6a and ClSCL6c reached their expression peak before the pollinating period, while ClSCL6b had the highest expression level in the period of small flower buds. This study laid the foundation for further studying on the role of ClSCL6 in floral transformation of C. lavandulifolium.

Abstract:The SOS signal transduction pathway is a salt stress signal response pathway in plants, and serine/threonine protein kinase (SOS2) plays an important role in this pathway. Based on the cucumber genome database, this study used bioinformatics and quantitative realtime PCR and other methods to identify the whole genome of cucumber SOS2 gene family, and systematically analyzed its expression characteristics. The results showed that: (1) a total of 15 SOS2 genes (CsSOS21-CsSOS215) were identified in the cucumber genome, which were distributed unevenly on 5 chromosomes, and the subcellular localization showed that SOS2 protein were mainly located in the plasma membrane. (2) Phylogenetic analysis showed that CsSOS22 and CsSOS26 were more closely related to AtSOS2. (3) The prediction of cisacting elements shows that the promoter sequence of SOS2 gene mainly contains droughtinduced and defensestress response elements. (4) Structural analysis showed that the sequence of conserved motifs contained in SOS2 protein were completely consistent, and mainly contained STKc and NAF conserved domains, which may play a regulatory role in gene response to salt stress. (5) Quantitative realtime PCR test showed that the SOS2 gene family is mainly upregulated in cucumber roots and leaves in response to salt stress. Among them, 6 genes were upregulated in response to salt stress on the first day of treatment. As the treatment time prolonged, gene expression was downregulated under salt stress. Addition of polyamines significantly increased the expression of CsSOS21—CsSOS25, CsSOS28, CsSOS29, CsSOS212 and CsSOS215 in different tissues. This shows that polyamines can induce the expression of cucumber SOS2 gene family under salt stress, and then participate in the regulation of plant salt tolerance molecular network.

Abstract:In this study, Cladonia yunnan was collected from the Fenghuang Mountains of southwest China in 2016. The algal photobiont of C. yunnan was successfully cultivated by dilution pipetting and direct methods under axenic conditions. Based on both morphological examination and phylogenetic analysis of molecular data, the results showed that: (1) the investigated photobiont was the only algae isolated from the C. yunnan, spherical or ellipsoidal, asexual reproduction, nonmotile unicellular green alga (cell size of approximately 2.5 to 6 μm), containing a parietal chloroplast with a central pyrenoid surrounded by starch. 3-5 cells enfold in a mucilaginous jelly. The cell nucleus was barely visible. (2) Based on our morphological characterization, the photobiont was similar to Coccomyxa subellipsoidea (freeliving). The photobiont is accordingly named Coccomyxa sp. YN with YN referring to the collection location (Yunnan, China). (3) Based on rbcL and ITS data, Coccomyxa sp. YN and C. subellipsoidea constituted one clade. ITS2 secondary structure were compared between Coccomyxa sp. YN and C. subellipsoidea. They have almost identical ITS2 secondary structure. Overall, this study reveals for the first time that Coccomyxa was the photobiont of Cladoniaceae. Coccomyxa sp. YN was closely related to C. subellipsoidea. Nonetheless, based on our morphological characterization, the Coccomyxa sp. YN may be modified in the lichenized state that is distinct from the closely related C. subellipsoidea. We speculate that photobionts may have evolved from freeliving algal cells.

Abstract:Semiaquilegia is an Asia endemic genus in the Ranunculaceae, but the data on floral morphogenesis of this genus, are still lacking. In this paper, we used scanning electron microscopy to study the floral development of S. adoxoides (DC.) Makino to indicate the flower diversity and phylogeny and further to provide morphologic development evidence of S. adoxoides and its related plants. Our results indicate that: (1) the sepals, petals and stamens of this genus are initiated spirally, whereas the carpels are initiated whorled. The staminodium number and positions are not sure. The phyllotaxis is whorled. (2) Primordia of the sepals are lunular and truncate, but those of other organs are hemispherical and rounded. (3) Petal development is delayed and there is an abaxial knob at the base. The carpel primordia are plicate, and mature ovule is anatropous and unitegmic. There is an appendage on the placenta. (4) Semiaquilegia shows similar floral development features as Aquilegia and Urophysa, which supports the relationship inferred by DNA sequence data. At the same time, other characters, e.g. small flowers, few stamens, sterile stamens, and carpels, absent orthostichies, longer inner integument, support Semiaquilegia as a distinct genus.

Abstract:In order to clarify the anatomical characteristics of the vegetative organs of ‘Caoyuan No. 4 alfalfa’ with extremely strong insect resistance properties, we selected ‘Caoyuan No. 2 varia alfalfa’ which has antithrips characteristics as a control, and used microscope to compare the anatomical structure characteristics of the roots, stems, and leaves of the two varieties, to reveal the antithrips characteristics of ‘Caoyuan No. 4 alfalfa’ to provide a theoretical basis. The results showed that: (1) the thickness of the cortical parenchyma, the thickness of the endothelium, the thickness of the cambium, the thickness of the xylem and the width of wood rays of the root anatomical structure of ‘Caoyuan No. 4 alfalfa’ were all significantly higher than that of ‘Caoyuan No. 2 varia alfalfa’, in which the wood beam width (159.37 μm) is 1.82 times of ‘Caoyuan No. 2 varia alfalfa’ (P＜0.01). (2) The thick horn tissue thickness (21.4 μm) of the stem of ‘Caoyuan No. 4 alfalfa’ is extremely significantly higher than that of ‘Caoyuan No. 2 varia alfalfa’ (P< 0.01), while the phloem width and pith diameter are significantly lower than that of ‘Caoyuan No. 2 varia alfalfa’ (P< 0.01). (3) The seven indicators of leaf anatomical structure of ‘Caoyuan No. 4 alfalfa’ are significantly higher than that of ‘Caoyuan No. 2 varia alfalfa’ (P< 0.01), and the number of palisade tissue layers (2～3 layers) is extremely obvious higher than that of ‘Caoyuan No. 2 varia alfalfa’ (1~2 layer). Studies have shown that the tissue structure of ‘Caoyuan No. 4 alfalfa’ has obvious insect resistance characteristics, and its tissue resistance is more prominent than ‘Caoyuan No. 2 varia alfalfa’.

Abstract:In order to investigate the intrinsic mechanism of sucrose participated in drought tolerance in plants, the study used the phosphoenolpyruvate carboxylase (C₄pepc) transgenic rice (Hereinafter referred to as PC) and untransformed wildtype “Kitaake” (Hereinafter referred to as WT) rice lines. PC and WT were treated with different concentrations of sucrose during seed germination under simulated drought treatment (10% PEG6000). The performance of seed germination, total soluble sugar and sugar components contents, total soluble protein content, transcript levels of genes of sucrose nonfermenting1(SNF1)related protein kinases (SnRKs) and transcript levels of PEPC genes in rice lines were measured. The results showed as following: (1) external application of sucrose solution showed the similar effect with the seed germination of rice, but significantly promoted the seed germination with low concentration of sucrose solution companying with drought treatment. External application of sucrose solution showed a concentrationdependent effect on seed germination of two rice lines. High sucrose concentration (>150 mmol·L^-1) further inhibited drought effect, while low concentration (<30 mmol·L^-1) alleviated drought inhibition. However, the sensitive concentration of sucrose with the best effect on seed germination was different in two lines under drought treatment, PC (<6 mmol·L^-1) is much lower than WT (<30 mmol·L^-1). And this performance is consistent with the dynamic changes of the activity of αamylase in two lines as well. (2) Compared with WT, 3 mmol·L^-1 sucrose combined with drought treatment significantly promoted the performance of seed germination in PC with a significant increase of endogenous sucrose content, total soluble sugar content and soluble protein content. Furthermore, the treatment of 3 mmol·L^-1 sucrose with drought significantly decreased the transcript level of C₃pepc, but significantly increased C₄pepc in the PC, respectively (P<0.05); (3) Some sugar signaling related genes such as SnRKs family genes including SnRK1s (OsK1a OsK24 OsK35) and SnRK2s (SAPK6) in PC rice also significantly increased their transcript levels after the same treatment as above. The results showed that PC can increase the contents of soluble sugar and soluble protein, regulate the expression of SnRKs subfamily genes and exogenous C₄pepc by increasing low sucrose, improve the activity of αamylase, and therefore alleviate the inhibitory effect on the seed germination under drought treatment.

Abstract:Using by hydroponic and potted methods, we explored different concentrations of Cd stress for Celosia cristata L. seed germination, biomass of seedlings, photosynthetic pigment, soluble protein, soluble sugar, proline and MDA contents, antioxidant enzyme activities (SOD, POD, CAT, APX) and low molecular sulfhydryl compounds (GSH, GSSG, Cys, NPT) contents to explore the ability of C. cristata L. to withstand Cd stress and its physiological mechanism, and to provide basic information for plant detoxification mechanism. The results showed that: (1) the germination potential, germination rate and germination index of C. cristata L. seeds were increased under the treatment of low concentration Cd, while the vigor index, root length and seedling length were reduced to varying degrees under Cd stress at various concentrations, and the above indicators were significantly inhibited under high concentration (50, 100 mg/L) Cd stress, and the degree of root growth inhibition was significantly higher than that of seedlings. The biomass of seedlings (whole plant fresh weight, fresh weight above ground and fresh weight underground) showed significant differences in 200 mg/L Cd stress, which decreased by 61.9%, 58.4% and 72.7% respectively compared to control, and although there was no significant difference between the rootshoot ratio and the taproot length, the overall trend decreased, greatly affecting the growth of the roots. (2) The chlorophyll and carotenoids contents of C. cristata L. seedlings were significantly reduced under the stress of 100 to 200 mg/L Cd concentration, and the contents of leaf soluble protein, soluble sugar and proline increased significantly under Cd stress, and increased significantly at 50, 150, 200 mg/L, respectively. (3) The POD and APX activities increased by 23.1%-304.2% and 160.0%-280.0% in all Cd treatments, respectively; The SOD activity decreased in all Cd stress treatments, and decreased significantly by 43.2% under 150 mg/L Cd stress; The CAT activity increased significantly by 46.6%-66.5% under 50-150 mg/L Cd stress, while decreased significantly by 59.5% under 200 mg/L Cd stress. (4) The low molecular sulfhydryl compounds GSH, GSSG, Cys and NPT increased by 53.2%, 164.2%, 53.9% and 0.79%, respectively, under high Cd concentration (200 mg/L), while the GSH/GSSG ratio decreased significantly. The study found that C. cristata L. seed germination period and seedling stage have a certain tolerance to Cd stress, but the high concentration Cd stress still leads to the reduction of antioxidant enzyme activities in the seedling part, the excessive accumulation of ROS, resulting in a deeper degree of membrane lipid peroxidation, the product MDA content gradually increased; Cd stress promotes a different increase in low molecular sulfhydryl compounds, but the GSH/GSSG ratio decreases and the incell Redox is inhibited, which causes the normal growth metabolism of seedlings was blocked and the biomass decreased continuously.

Abstract:In order to clarify the effects of water deficit and rehydration on the assimilation transport and grain filling of wheat after anthesis, we applined three treatments, named, well water (WW), rehydration after moderate drought stress (MD) and rehydration after severe drought stress (SD), after 9 days flowering in pot experiment with wheat cultivar ‘Changhan 58’. The yield, grain filling dynamics, photosynthetic performance of flag leaves, nonstructural carbohydrate (NSC) transport in stem and sheath and the activities of key enzymes in grain, were investigated during the process of drought and rehydration. The results showed that: (1) compared with WW treatment, MD significantly increased the number of grains per spike and thousandgrain weight of wheat and thus improving the grain yield, water use efficiency and maximum grouting rate of grains and the average filling rate. For the SD treatment, grain numbers per spike, the superior and inferior spikelets of maximum grouting rate and the average filling rate were significantly decreased, but the water use efficiency was significantly increased compared with WW. (2) The photosynthetic rate of flag leaves during wheat filling had no difference between MD treatment and WW treatment. Meanwhile, compared with WW, stomatal conductance and transpiration rate at 9-20 d after wheat flowering were not changed under MD, while they were profoundly decreased under SD. (3) The activities of sucrose synthase and adenosine diphosphate glucose pyrophosphorylase in wheat was increased by MD treatment; Meanwhile, MD had lower fructose content, which suggested that contribution of substances in stem to the yield were increased. The study found that higher photosynthesis, more assimilates in the stem after anthesis transfer to the grain and higher sugar metabolism enzyme activity in the inferior spikelets, and the number of grains per spike and thousandgrain weight, then finally increase the physiological basis of yield.

Abstract:We used the seedings of 22 wild loquat (Eriobotrya japonica Lindl.) germplasm from Guizhou Karst area as the test materials in the experiment, and the method of soil culture and nutrient solution culture experiment in this study. The plant height, and dry weight, nitrogen content, absorption amount and uptake efficiency of NH⁺₄N, nitrogen use efficiency, maximum uptake rate (I_max) of NH⁺₄, the Michaelis constant value (K_m), the flow rate of NH⁺₄ into root (α) of 22 wild loquat germplasm seedlings under different NH⁺₄N levels were tested. The difference, interaction and correlation between the above indexes were analyzed and evaluated，and nutrition efficiency type of different wild loquat germplasm was divided. The results showed that: (1) the dry weight of seedlings, nitrogen absorption amount and nitrogen efficiency in different germplasm and NH⁺₄N levels were significantly different. The coefficient variation (CV) of seedlings dry weight, nitrogen content, absorption amount and uptake efficiency of NH⁺₄N，and nitrogen efficiency were 21.09% and 16.87%, 17.06% and 20.00%, 36.67% and 40.21%, 36.71% and 40.24%, 21.05% and 19.21%, respectively among 22 wild loquat germplasm seedlings. The difference of NH⁺₄ absorption kinetic parameters among different wild loquat germplasm were very obvious. The CV of I_max, K_m and α under high nitrogen and low nitrogen levels were 44.64% and 60.00%, 73.53% and 81.48%, 89.58% and 109.18%, respectively. (2) Among all the above indicators, the differences and interactions in different germplasm and two NH⁺₄N levels were extremely significant (P <0.01), the dry weight of seedlings, nitrogen content, absorption amount and uptake efficiency of NH⁺₄N, nitrogen efficiency, I_max and α of NH⁺₄ all had extremely significantly positive correlation of 22 wild loquat germplasm, while the K_m was extremely significantly negative correlation to above indexes. Under high nitrogen and low nitrogen levels, the direct path coefficient of NH⁺₄N absorption efficiency to nitrogen efficiency was the largest (1.805 and 1.523), and the direct contribution was also the most. (3) Through the above filter, 22 wild loquat germplasm were classified into four nitrogen efficiency types: efficient under high nitrogen and low nitrogen, efficient under high nitrogen, efficient under low nitrogen and inefficient under high nitrogen and low nitrogen. There were 7, 4, 2 and 9 germplasm, respectively. The studies showed that the different of uptake and use efficiency for ammonium nitrogen among 22 wild loquat germplasm of Guizhou Karst area were significantly different. The dry weight of seedlings, absorption amount and uptake efficiency of NH⁺₄N, and nitrogen efficiency can be used as evaluation and filter indexes of nitrogenefficient loquat germplasm.

Abstract:In order to explore the difference of growth and element accumulation of Populus davidiana seedlings under the combined of compound treatment of cadmium (Cd) and exogenous nitrogen (N), we studied the effects of N on morphology, chlorophyll, starch and soluble sugar contents, total nitrogen (N), total phosphorus (P), total potassium (K) and Cd content in leaves under Cd stress by pot experiment. The results showed that： (1) the leaf width and stem diameter of P. davidiana were significantly inhibited by Cd alone. The toxicity of Cd to plants was compensated by exogenous N under Cd stress, and the leaf length, leaf width and stem diameter were significantly increased compared with Cd treatment alone. (2) Compared with the control, the chlorophyll content and starch content of P. davidiana leaves decreased significantly after Cd treatment, while the soluble sugar content increased significantly. Compared with Cd+N treatment, the chlorophyll content increased significantly, the starch content decreased significantly, and the soluble sugar content decreased slightly. (3) Compared with the control, the total N content and total P content of P. davidiana leaves decreased significantly after Cd treatment. The total N content increased significantly and the total P content decreased significantly after N treatment and Cd+N combination treatment. However, there was no significant difference in total K content among all treatments. (4) Under Cd stress, the Cd content in leaves of P. davidiana seedlings was significantly increased compared with the control, and the Cd content in leaves of Cd+N composite treatment was about twice as much as that of single Cd treatment. The results showed that the adaptability of P. davidiana seedlings and Cd accumulation ability of leaves could be improved by increasing N application under Cd stress.

Abstract:To explore the influence of shading treatment on the flowering characteristics and volatile composition of Gardenia jasminoides, and to provide reference for scientific planting, maintenance and volatile composition regulation of ornamental gardenia, this study used two kinds of Gardenia jasminoides var. grandiflora and Gardenia jasminoides var. radicans as test materials, with five different shading treatmentsCK₁ (total illumination contrast, no shading), CK₂ (under the shade of Eucommia ulmoides, the shading rate was 80%), T₁ (one needle and one layer of shade net, the shading rate was 60%), T₂ (two needles and layer of shade the shading rate was 70%), and T₃ (two needles and two layers of shade, the shading rate was 90%). We researched and measured their flowering characteristics (flowering time, flowering duration, number of flowers, opening rate and morphological characteristics of flowers). We collected flowers, determined volatile composition and relative contents of two kinds of gardenia by using SPMEGCMS. The results showed that: (1) proper shading advanced the flowering time of the two gardenias, and had no obvious effect on the flowering duration. Severe shading delayed the flowering time of the two gardenia and shorten flowering duration. The bud number and normal flower number of CK₁ treatment were the highest in 5 treatments, and the open rate of CK₁ and T₁ were not significantly different, and higher than that of other treatments. (2) With the increase of shading degree, the number of buds, the number of normal flowers and the opening rate were gradually reduced, and the flower diameter/bud length decreased with the increase of shading rate; (3) There were 26 compounds in 4 major groups, including alpha.Farnesene, 3Carene, (E)hex3enyl (E)2methylbut2enoate and Linalyl acetate in G. jasminoides var. grandiflora. A total of 23 compounds were detected in G. jasminoides var. radicans, and the main compounds were 3Carene, cis3Hexenyl tiglate, Benzoic acid, methyl esterand (3E, 7E)4, 8, 12trimethyltrideca1, 3, 7, 11tetraene. (4) CK₁ treatment of the to gardenia showed the most variety of volatile components and decreased with the increase of shading rate, among which terpene substances increased first and then decreased with the increase of shading rate, and esters decreased first and then increased with the increase of shading rate. Shading treatment had great influence on the flowering characteristics and volatile composition of G. jasminoides var. grandiflora and G. jasminoides var. radicans. There was no significant difference in the effect of shading on the flowering characteristics of the two different species of gardenia, but there were significant differences in the composition and relative contents of volatile. In the arrangement of garden plants, it is suggested that ornamental gardenia should be planted in moderate shading environment, such as deciduous trees, and avoid planting in heavy light and heavy shading environment as far as possible.

Abstract:Using 6 species of Calanthe s. l. plants and 2 kinds of Epiendroidea plants as materials, we determined indican, isatin, indigo and indirubin contents in flowers and leaves before and after freezing treatment with liquid chromatographytandem triple quadrupole mass spectrometer (LCMSQQQ). Analyzed the content of indoxyl derivatives of Calanthe s. l. plants and the differences between species. The results showed that: (1) these 4 indoxyl derivatives were detected in all the 6 Calanthe s. l. plants, but not in the 2 Epidendroidea plants Doritis pulcherrima and Eria coronaria. (2) In the flowers and leaves of 6 Calanthe s. l. plants, the contents of indigo, indirubin and isatin increased significantly after freezing treatment, while the content of indican decreased significantly. At the same time, the content of indoxyl derivatives in flowers was higher than that in leaves. (3) The total content of indoxyl derivatives in the flowers and leaves of the 6 Calanthe s. l. plants were the highest in Cephalantheropsis gracilis flowers and the lowest in Calanthe triplicata leaves. This work has shown that the massive conversion of indican to indigo caused by freezing treatment is the main reason for the blue color in the tissues of the Calanthe s. l. after freezing. It is speculated that indoxyl derivatives may also be a class of compounds related to plant defense and play an important role in plant resistance to adversity.

Abstract:By analyzing the shortterm community dynamics of evergreen deciduous broadleaved mixed forest in Mulinzi subtropical mountain area of Southwest Hubei Province, this study provides scientific basis for the protection, restoration and sustainable management of forest ecology in this area. Based on the 2.2 hm² dynamic monitoring sample plot of Mulinzi Nature Reserve, all woody plants with DBH (≥ 1 cm) in 2014 and 2019 were selected as the research objects, and the dynamic changes were analyzed from the aspects of species composition and diversity, important value, mortality, recruitment rate and DBH, etc. The results show that: (1) during the five years, the number of woody plants decreased from 17 308 to 16 533, with a decrease rate of 4.48%. The basal area at breast height increased from 31.42 m²·hm^-2 to 35.53 m²·hm^-2. 18 species of 6 genera in 1 family increased, and 7 species in 1 genus disappeared. Margalef richness index of arbor, sub tree, shrub and liana increased, while the Pielou evenness index decreased. Except for trees, the ShannonWiener diversity index and Simpson index of the other three growth types increased. (2) There were 1 269 recruitment individuals with an average DBH of 2.44 cm, the basal area at breast height of 0.32 m²·hm^-2, and an average increase of 115.36 plants·hm^-2·a^-1, belonging to 39 families, 59 genera and 99 species. There were 2 044 mortality individuals with an average DBH of 3.32 cm, a chest height of 1.31 m²·hm^-2 and an average of 185.82 plants·hm^-2·a^-1, belonging to 146 species, 90 genera and 51 families. There were significant differences in the number of supplement members and dead individuals in different diameter classes, which decreased with the increase of diameter class. (3) Among the 46 main species, 15 important values increased and 31 decreased. The range of increase and decrease was tree layer > shrub layer > subtree layer. The average DBH increased from 4.70 cm to 5.12 cm. The average DBH of Castanea henryi decreased, but the average breast height of other species increased. (4) Among the main tree species, 44 were growth type population, and the other two species had the same population growth rate. The annual recruitment rate of main species was greater than the annual mortality rate. The mortality rate of different growth type species and their different diameter classes were different. Generally speaking, the recruitment rate of different diameter classes was greater than the mortality rate. However, with the increase of diameter class, the difference between recruitment rate and mortality rate gradually decreased and tended to be flat. In general, The change range of species composition and diversity, the important value and average DBH of main species was small, and no obvious fluctuation occurred. The regeneration dynamics of different diameter classes of main species were different, but not violent. Therefore, the appearance of the whole community remained basically unchanged and the development was relatively stable.

Abstract:Lichen is a kind of important biological resource of desert steppe at the eastern foot of Helan Mountain, Ningxia. The formation of the lichen crusts has made an important contribution to the stability of the regional landscape. The field investigation of lichens was carried out from 2014 to 2019 in the desert steppe of the eastern foot of Helan Mountain, and more than 500 speciemens were identified using phenotypic characteristics and DNA sequence analysis, both the species composition and biogeography were analyzed. The results showed that: (1) a total of 74 species belonging to 41 genera and 19 families were identified, with 2 taxa new to science (in press), 25 taxa and 11 genera representing new records for China, and 56 taxa new records for Ningxia. (2) The most important biogeographical element of lichen was north temperate element (33.78%), other main elements included Eurasian and cosmopolitan. The results showed that the area had a distinct north temperate character in floral composition. (3) Crustose and squamous lichens accounted for a high proportion (81.1%), which embodied the characteristics of the lichen species adapt to the local climate conditions. The field survey showed lichen habitats in the desert steppe of Ningxia Helan Mountain were very fragile. This study is helpful to improve the understanding of lichen species diversity and promote its conservation in the area.

Abstract:More than 100 Rinodina specimens collected from Xinjiang were used in this study. Nine species were identified through morphological and anatomical observation, lichen chemical composition analysis and molecular biology identification methods. Among them, two species named Rinodina afghanica and R. guzzinii are firstly recorded in China. Other seven common species are R. bohlinii, R. bischoffii, R. metaboliza, R. pycnocarpa, R. trevisanii, R. straussii and R. terrestris. The detailed descriptions, pictures showing characteristics of new recorded species, phylogenetic analysis and the key to species are provided.