Abstract:The variations of functional traits and ecological strategies of population may greatly affect its adaptive capacity and the structure of a community. Based on the multiple functional traits of the ramet groups at the different developmental stages of 3 subpopulations of Phragmites australis in Chongming Dongtan wetland, this paper analyzed its intra-population variations of functional traits and ecological strategies, and made an ordination of the ecological strategies of each subpopulation based on the CSR and LHS schemes. The results showed that 21 functional traits, C and R strategy scores among the 3 subpopulations of P. australis were significantly different. In the LHS scheme, 3 subpopulations were separated along the boundary line of the specific leaf area (11.5 mm²/mg), plant height (175 cm) and inflorescence dry weight (4 g). Ramets at the reproductive growth stage were characterized by larger plant sizes, higher leaf dry matter contents and S scores, while those at the vegetative growth stage, the smaller plant sizes, larger specific leaf areas and R scores. In general, there were significant differences in functional traits and ecological strategies among 3 subpopulations and between the ramet groups at the different developmental stages, and the divergent pattern of functional traits and ecological strategies were basically consistent. These might provide important theoretical reference and technical support for the ecological conservation and restoration of P. australis population in this area.

Abstract:Waterfowl activities transport nutrients, such as nitrogen and phosphorus, to terrestrial habitats, and cause soil nutrient enrichment, which may change the vegetation communities, and species richness of habitat ecosystems. To investigate the influence of waterfowl inhabitation on soil physicochemical properties and plant community characteristics, the changes in plant community and soil physicochemical property were studied in Shunde Waterbird Paradise, Xinghu Wetland, and Jiangmen Little Bird Paradise of Guangdong Province. The results showed that waterbird activities significantly increased the soil total phosphorus, available phosphorus, and inorganic phosphorus contents. In Shunde and Xinghu, the organic phosphorus content of the inhabited area was significantly higher than that of the control area. The plant richness and Shannon diversity index of inhabited areas were significantly lower than those of the control area. The total explanation rate of four environmental factors, including soil pH, density, organic matter, and available phosphorus, on plant community variation were 46% (P＜0.05), among which available phosphorus was the most influential factor. Therefore, it was suggested that waterbird activity significantly increases the contents of various phosphorus fractions in the soil and decreases plant diversity.

Abstract:In order to investigate the effects of cadmium (Cd) pollution and its combinations with elevated atmospheric CO₂ concentration and nitrogen (N) addition on N and phosphorus (P) utilization strategies and Cd accumulation in leaves, two afforestation tree species (Acacia auriculiformis and Cinnamomum camphora) were selected, and the open-top chambers (OTCs) was used to construct the simulated experimental forests of the two tree species. The five treatments were control (CK), adding Cd [10 kg Cd/(hm²·a)] (Cd), adding Cd and CO₂ (700 μmol/mol) (CdC), adding Cd and N [100 kg N/(hm²·a)] (CdN), adding Cd, CO₂ and N (CdCN). After treatment for about 2.5 years, the mature and senescent leaves of two tree species were collected to measure the concentrations of N, P and Cd. The results showed that the foliar P concentration and P resorption efficiency had no significant changes under different treatments, but the N concentration and N resorption efficiency in leaves were significantly affected. The N concentration in leaves of two species increased under CdN treatment, and the N resorption efficiency in C. camphora leaves decreased significantly under Cd and CdN treatments. Under the treatments of Cd, CdC, CdN and CdCN, the Cd accumulation in leaves of two species, as well as the Cd/N and Cd/P ratios in mature leaves of C. camphora increased. The N and P resorption efficiencies were significantly higher, while the Cd accumulation was significantly lower in A. auriculiformis than those in C. camphora. It was demonstrated that the fast-growing leguminous N-fixing tree species (A. auriculiformis) had better N and P utilization strategies and stronger resistance to Cd accumulation than the common non-N-fixing tree species (C. camphora), suggesting that A. auriculiformis could be suitable for ecological restoration in Cd polluted forest sites.

Abstract:To understand the changes in species diversity of Emmenopterys henryi community and its driving factors, 35 sample circles with a 15 m radius centered on an E. henryi tree were set up in the Jiulongshan National Nature Reserve, Zhejiang Province. The species and diameter at breast height (DBH) of arbor layer trees (i.e. woody plants with a DBH more than 2.5 cm) within the sample circles were investigated. The relationship between α diversity of arbor layer trees and altitude, and slope aspect, and DBH of E. henryi in each sample circle were analyzed by linear mixed model, and the influences of spatial structure, altitude, and slope aspect, and DBH of E. henryi on β diversity were studied using the mantel test and variation partition analyses. The results showed that the number of species in arbor layer of E. henryi communities was rich, with 145 woody species belonging to 98 genera and 50 families, and dominated by deciduous or semi-evergreen species. The Shannon-Wiener index ranged from 2.37 to 3.40 and the Simpson index from 0.86 to 0.94. The α diversity indices increased at first then decreased with elevation, and neither related to the slope aspect nor DBH of E. henryi. The Sorenson index of community pairs ranged from 0.15 to 0.95 and the contribution of turnover components to the total β diversity of arbor layer was 74.88%. The geographical distance between sample circles was significantly positively correlated with β diversity and its components of arbor layer trees; while the altitude difference between sample circles was significantly positively correlated with β diversity and species-richness difference of arbor layer trees. The DBH difference of E. henryi between sample circles was only positively correlated with species turnover of arbor layer trees. The geographical distance of the sample circles is the likeliest explanation for β diversity and its two components (23%–29%) of arbor layer trees. The altitude difference is also a probable explanation for β diversity of arbor layer trees (16%). Therefore, α diversity of arbor layer trees in the E. henryi community in Jiulongshan was mainly affected by altitude, while β diversity and its two components of arbor layer trees were affected by dispersal limitation, habitat filtering, and interspecific interaction between E. henryi and associated species.

Abstract:In order to understand the field long-term effect of biochar-based fertilizer instead of chemical fertilizer, the vegetable yield, soil physical and chemical properties and bacterial community structure with biochar-based fertilizer replacement for 5 consecutive years were studied by localization experiment. The results showed that soil pH increased 0.13-0.25 after 5 years, and the contents of organic matter, alkali-hydrolyzable nitrogen and available phosphorus in soils increased 2.1%-62.2%, 5.8%-86.0% and 0.4%-103.1%, respectively. The yield of Capsella bursa-pastoris with biochar-based fertilizers increased by 4.0%-14.8% than that of the control, but the yield under 75% replacement was lower than that of 50% replacement. The indexes of Sobs, Shannon, Ace and Chao of soil bacteria with biochar-based fertilizer were higher than those of chemical fertilizer, and those under 75% replacement were the highest. Compared to chemical fertilizer, the abundances of Nitrolancea, Amycola- topsis and Gemmatimonas with biochar-based fertilizer decreased significantly, and the abundances of cellulose-degrading bacterial increased, such as Planifilum and Saccharimonadales. There were significant correlations between the abundances of Gemmatimonas, Ilumatobacteraceae, Methyloligellaceae, and soil total nitrogen, total phosphorus, organic matter. Therefore, the replacement of continuous biochar-based fertilizer significantly improved soil physical and chemical properties, and caused the changes in bacterial community structure and diversity. Appropriate replacement of biochar-based fertilizers could increase vegetable yield, but the effect of long-term continuous application on soil pH and C/N should be paid attentions, so as to avoid excessive application inhibiting nutrients uptake and utilization by crops.

Abstract:In order to understand the diversity of bryophytes and their response to gap disturbance in dark coniferous forests in Xizang Sygera Mountain, the biomass characteristics of epiphytic bryophytes on the ground, rotting wood and tree in different habitats (forest gap, forest edge, understory) were studied in five plots of western slope in Xizang Sygera Mountains. The results showed that the biomass per unit area of ground bryophytes were the highest with an average of 910.10 g/m², followed by saprophytic bryophytes (221.90 g/m²) and epiphytes (53.59 g/m²). The biomass per unit area of ground moss in the forest gap was the highest with an average of 360.47 g/m², followed by understory (305.51 g/m²), and forest edge (244.11 g/m²). There was a significant difference in the biomass per unit area among three habitats (P＜0.05). Along altitude gradients, the biomass per unit area of bryophytes grown in forest gap increased at first and then decreased. Therefore, it was suggested that the forest gap had a significant effect on the biomass per unit area of ground moss in dark coniferous forest in Xizang Sygera Mountain.

Abstract:Several foliage horticultural varieties have been bred based on Spiraea × vanhouttei, including ‘Pink Ice’ and ‘Gold Fountain’, which exhibit excellent horticultural traits. However, the underlying mechanism of these two colorful leaf varieties remain poorly understood. To address this knowledge gap, the complete chloroplast genomes of ‘Pink Ice’ and ‘Gold Fountain’ were assembled by using genome skimming sequencing. Comparative genomic analysis of all available chloroplast genomes of the genus Spiraea to date was studied, including variation hotspot analysis, simple repetitive sequence analysis, and phylogenetic analysis. The results showed that both varieties had a typical quadripartite structure, consisting of one LSC, one SSC, and two IRs. The chloroplast genomes of ‘Pink Ice’ and ‘Gold Fountain’ were 155 953 and 155 941 bp in size, respectively, and each contains 130 genes, including 85 protein-coding genes, 37 transfer RNA genes and 8 ribosomal RNA genes. The two chloroplast genomes also contained 67 and 69 simple repetitive sequences, respectively, with single nucleotide repeat sequences being the most abundant. There were seven highly variable regions within these two chloroplast genomes, including trnH_GUG-psbA, trnK_UUU, trnR_UCU-atpA, trnT_GCU-psbD, ndhC, rpl32, and ycf1. Finally, phylogenetic analysis revealed that ‘Pink Ice’ and ‘Gold Fountain’ could not be considered a monophyletic group, despite their close relationship. Overall, these would provide valuable insights into the chloroplast genomes of two foliage varieties of Spiraea, which would aid in the development of more horticultural resources for this genus in the future.

Abstract:Protein kinases (PKs) and transcription factors (TFs) are important components of signal transduction, which are involved in the secondary growth of stems. To explore their expression changes in stem secondary growth of albino Artocarpus heterophyllus seedlings, the differentially expressed genes (DEGs) of PKs and TFs were predicted and classified based on transcriptome data, and phylogenetic trees were constructed for 2 PKs and 4 TFs families. The results show that the number of up- and down-regulated DEGs in the receptor-like cytoplasmic kinase (RLCK)-VIII family was 4 each. All of DEGs in Xa and Xb-2 branches in leucine-rich repeat receptor kinase (LRR-RLk)-X family were down-regulated, while those in Xb-1 branch were up-regulated. Among 20 DEGs in TCP family, 15 were up-regulated in AAS. And most genes in zf-HD and GRF families were up-regulated, while all DEGs in Alfin-like were down-regulated in AAS. Therefore, it was suggested that six families might play an important role in the secondary growth of A. heterophyllus stems and the response to abiotic stress.

Abstract:In order to explore the genes related to pine resin biosynthesis in Pinus elliottii, a total of 12 samples of xylem at different resin collection stages and needles were used for high-throughput transcriptome sequencing. Compared with the reference genome of P. taeda, a total of 68 211 unigenes and 546 356 450 clean reads were obtained with an average mapping rate of 90.21%. The expression profiles between needles and xylem were compared in pairs. The differentially expressed genes (DEGs) were selected according to P＜0.05,|log₂foldchange|> 1.0, and then annotated by GO and KEGG enrichment analysis. The results showed that 133 DEGs involved in terpene synthesis, most of which were enriched in MEP pathway. Eight candidate genes related to pine resin biosynthesis were selected from the DEGs and validated by RT-qPCR, in which HMGR, DXS, TPS, ABC transporter genes were highly correlated with the rosin production. Therefore, 133 differential genes related to pine resin biosynthesis were mined through transcriptome sequencing, and among which three TPS genes and two ABC transporter genes positively regulate terpenoid synthesis.

Abstract:As a newly discovered chloroplast gene in recent years, ycf94 gene, with length of about 200 bp, is conserved among ferns. However, the origin and function of ycf94 require further investigation. The study was performed on the ycf94 gene sequence of 94 species of ferns, in the phylogenetic background, analyzing codon usage bias, evolution rate and selection pressure. Results showed that the codon bias was weak in ycf94 gene which the 3rd position of codon prefers A/U, variously in closely species. The codon bias was mainly produced by gene mutation. In addition, based on the differences in the structural characteristics of ycf94 between Pteridaceae and other ferns, their evolution rate was compared, suggesting that there were significant difference in transversion rate, nonsynonymous substitution rate and omega. Besides, only one position selection site 74A was detected. The strong negative selection pressure indicated that the function and structure of ycf94 were mostly stabilized. The results provide a new clue of phylogenetic analysis in ferns and functional studies of ycf94 gene.

Abstract:In order to understand the mechanism of continuous cropping obstacles, the changes in soil properties after continuous cropping of Stevia rebaudiana were studied, and the correlations between soil properties and leaf dry mass and stevioside were discussed. The results showed that there were no significant differences in soil pH, organic matter, available phosphorus, urease, catalase, sucrase, phosphatase, leaf dry weight and stevioside components between 2- and 3-year continuous cropping. However, after continuous cropping for 4 years, soil pH, total nitrogen and available potassium decreased significantly, which were 10.07%, 14.38% and 24.79% lower than the control, respectively. But the soil electric conductivity (EC) and available phosphorus increased significantly with 2.57 and 1.70 times to the control. Meanwhile, the activities of urease, sucrase, alkaline phosphatase, microbial biomass carbon and microbial biomass nitrogen in soil were 63.68%, 72.03%, 47.43% and 78.35% lower than the control, while the activity of polyphenol oxidase reached the highest, which was 4.22 times to the control. Compared with the control, leaf dry weight and stevioside decreased by 29.51% and 16.00%, while the content of rebaudioside A increased by 22.19%. There were correlations between leaf dry weight and stevioside content and soil properties. Therefore, it was suggested that continuous cropping affects the yield and quality of stevia by changing soil properties, and the maximum continuous cropping period in production should not exceed 3 years.

Abstract:To screen the differentially expressed genes (DEGs) and differential metabolites (DMs) that promote the growth of Dendrobium officinale, transcriptomic, metabolomic and biomic analysis were performed on the lateral roots formed after the symbiosis of tumorrhizal bacteria and sterile potted D. officinale seedlings. The result showed that a total of 262 DEGs were found and enriched into 35 pathways by transcriptome analysis, among which endoplasmic reticulum protein processing pathway had the most DEGs, followed by amino sugar and nucleotide sugar metabolism pathways. A total of 194 DMs were detected enriched in 33 KEGG pathways by metabolomic analysis, among which 133 DMs were in metabolic pathways, followed by 70 DMs in microbial metabolic pathways of different environments. Combined analysis showed that the differential expression of 9 DEGs resulted in changes in the accumulation of metabolites, such as serine, glutamate, d-mannose and hormones, which might be an important reason for Epulorhiza sp. to promote the growth of D. officinale. Therefore, it was suggested that the growth of D. officinale promoted by Epulorhiza sp. was related to the accumulation of amino acids, sugars, phytohormones and the expression changes of related genes.

Abstract:In order to understand the effect of mottle virus on the photosynthesis of yam (Dioscorea opposite) ‘Niuwei’, the diurnal changes in chlorophyll and photosynthesis in leaves with different degrees of mottle virus disease were measured. The results showed that the contents of chlorophyll a and total chlorophyll of mildly infected plants were significantly lower than those of healthy plants, and the contents of chlorophyll b and carotenoids of seriously infected plants were also lower than those of healthy plants, but there was no significant difference in chlorophyll b and carotenoids between mildly infected plants and healthy plants. After mottle virus infected yam, the net photosynthetic rate, stomatal conductance and transpiration rate of mildly and seriously infected plants were also lower than those of healthy plants, but the intercellular CO₂ concentration had not significant difference from that of healthy plants. Therefore, it was indicated that the photosynthetic efficiency of yam decreased after infected with mottled virus, thus causing the physiological function to be affected.

Abstract:Based on combined morphological and chemical data with phylogenetic analysis using nrDNA ITS sequences, four species in the lichenized genus Lecanora Ach. and Cladonia P. Browne., including L. layana Lendemer, L. baekdudaeganensis B. G. Lee & Hur, L. pseudargentata Lumbsch and C. caespiticia (Pers.) P. Gaertn., B. Mey & Scherb. from Dabie Mountains, are reported as new record to China. The taxonomic characteristics of these species are described in detail and compared with similar species, and the geographic distribution and morphological photos are provided. These will provide information for the species diversity of Lecanora and Cladonia in China.

Abstract:In order to compare the difference of volatile components in cut flowers of diploid and tetraploid Hedychium coronarium, the types of volatile components released from cut flowers were determined by headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) at initial opening, blooming and early decay stages. The relative content of each component was determined by the peak area normalization method, and the orthogonal partial least quadratic discriminant analysis (OPLS-DA) model was established for principal component analysis and variable importance projection (VIP) analysis. The results showed that there were 63 terpenoids, 40 phenylpropanoids, and 22 fatty acid derivatives identified from the cut flowers. The relative content of terpenoids was higher than that of the other components. The total volatile mass of tetraploid flowers was significantly higher than those of diploids at initial opening and blooming stages. The difference of volatile components between diploid and tetraploid groups was obvious, and the difference within the two ploid groups was within the normal range. About 63.7% representative characteristics of volatile compounds were clustered. The variance analysis of the volatile compounds showed that the dominant and minor compounds contributed to the difference between the diploid and tetraploid. During blooming and early decaying stages, α-ocimene was the dominant component of tetraploid with the highest relative content, while β-ocimene was the dominant component with the highest relative content in diploid and significantly more than that in tetraploid. The common dominant components and contributions of diploid and tetraploid were caryophyllene, linalool, cineole, α-farnesene, and methyl benzenecarboxylate. Therefore, the types and total contents of volatile components increased with quadrupling process, and the types and contents of volatile components at different periods of the same ploidy were also different. The main volatile components of H. coronarium were terpenes.

Abstract:The aim was to clarify the chemical constituents of Salvia cavaleriei. Sixteen compounds were isolated from the 95% ethanol extract by using chromatographic separation techniques, such as silica gel, LH-20, MCI, and HPLC methods. On the basis of spectral data, their structures were identified as β-sesquiphellandrene (1), 6R-(7R,11-dimethyl-10-ethenylene)-cyclohexenone (2), β-bisabolene (3), α-curcumene (4), 3,4-dihydroxy- phenylacetic acid methyl ester (5), vanillin (6), zingerone (7), 6-shogaol (8), octadecyl ferulate (9), vitamin E quinone (10), 5-hydroxymethyl-2-furaldehyde (11), thioacetic anhydride (12), 3,4-dihydroxyphenylacetic indazole (13), hexadecanoic acid (14), squalene (15), and hexacosane (16). Among them, compound 2 is a new natural compound. Moreover, all compounds were obtained from this plant species for the first time except for compounds 3, 4 and 6. Accordingly, compounds 2, 5, 9 and 12 were isolated for the first time from Labiatae, compounds 1 and 15 were obtained from Salvia genus for the first time.

Abstract:To understand the chemical constituents and antibacterial activities of Trigonostemon heterophyllus, six compounds, including five diterpenoids and one lignan, were isolated and purified by silica gel column chromate- graphy, gel column chromatography and high performance liquid chromatography. Based on spectroscopic data, their structures were identified as trigonochinene E (1), neoboutomannin (2), 6,9-O-dedimethyl trigonostemone (3), stelltian B (4), 3,4-secosonderianol (5), biondinin A (6). The inhibitory activity and MIC values of compounds against a Gram-negative bacterium, Escherichia coli, and a Gram-positive bacterium, Pneumococcus, were detected by Oxford Cup method and double dilution method. Compounds 1, 2, 3 and 5 had inhibitory effects on Escherichia coli with MIC values of 9.375, 18.75, 18.75 and 18.75 μg/mL, respectively. Compounds 2, 3, 4, and 6 were isolated from T. heterophyllus for the first time, and compound 4 was isolated from Trigonostemon genus for the first time. Except compound 4, all the other compounds had certain antibacterial activity, and compounds 1, 2 and 3 had stronger inhibitory effect on Escherichia coli than Kanamycin sulfate positive control.