Abstract:To explore the suitable density for young plantations of Erythrophleum fordii, standard plots were set in 6-year-old Erythrophleum fordii plantation with different densities (2 m×1 m, 2 m×2 m, 2 m×3 m, 3 m×3 m), the characteristics of soil physicochemistry and understory vegetation in young plantation were studied by using soil quality evaluation and grey correlation method. The results showed that the DBH and height of trees under the density of 2 m×3 m were optimal, which were 16.7% and 27.9% higher than the lowest level, and the total porosity, total N, nitrate N and ammonium N contents of soil, as well as shrub and herb diversities also were the highest. After analyzing the correlation between soil physical and chemical properties and plant diversity, soil chemical properties had the greatest influence on shrub and herb diversity. There were significant differences in soil physical and chemical properties and understory plant diversity of E. fordii plantation among different stand densities. Therefore, it was very important to select appropriate density for the sustainable utilization of soil fertility, management and cultivation of plantations.

Abstract:In order to understand the effects of the Dicranopteris pedata population with different coverage on soil carbon content and nutrient status of Phyllostachys edulis forest, the stability and ecological stoichiometric characteristics of soil aggregates in P. edulis forest under 7.75% (PE) and 63.25% (DD) coverage of D. dichoyoma in Changning County, Sichuan Province were studied. The results showed that the content of large aggregates in DD plot was significantly lower than that in PE plot, which caused the decrease of aggregate stability. Moreover, the contents of total organic carbon (TOC), total nitrogen (TN) and total phosphorus (TP) in DD plot were significantly lower than those in PE plot, and the decrease of TP was the largest, which made significant increase of soil C: N, C: P and N: P. There was no difference in the contents of TOC, TN, TP, C: N, C: P and N: P in litter leaves and fine roots of P. edulis between DD and PE plots, but the contents of TN and TP in litter leaves and fine roots of D. dichoyoma were significantly higher than those of P. edulis in DD plots. The correlation analysis showed that the TP content in fine roots of P. edulis and D. dichoyoma were significantly positively correlated with that in soil large marcroaggregate, microaggregate and small marcroaggregate. So the high coverage of D. dichoyoma in moso bamboo forest could decrease the stability of soil aggregates, and reduced the contents of TOC, TN and TP in soil, which could increase the absorption of N and P in soil aggregates with different size classes by changing the soil ecological stoichiometric characteristics, especially the absorption of P. It should be considered to adjust the coverage of D. dichoyoma in the extensive management of moso bamboo forest in southern Sichuan, in order to ensure the long-term sustainability of soil nutrient supply.

Abstract:To understand the influence of interspecific relationships on community structure of submerged plants, the interaction of Vallisneria natans with Hydrilla verticillata and Myriophyllum spicatum was studied in the middle and lower reaches of the Yangtze River with different combinations of species under different light levels (20% and 50% nature light). The results showed that the biomass, height and leaf number of V. natans co-cultured with M. spicatum had not significant changes under low light intensity. The biomass of root and root/leaf of V. natans decreased with co-cultured ratio of M. spicatum increasing. Under high light intensity, the biomass and leaf biomass of V. natans increased with co-cultured ratio of M. spicatum increasing, while the height, root length and leaf number of V. natans had not change. There were no significant differences in height, root length and leaf number of V. natans between co-cultured with H. verticillate and M. spicatum, while biomass and leaf biomass of V. natans co-cultured with M. spicatum were lower than those co-cultured with H. verticillate. Therefore, both the species composition and co-cultured ratio could affect the interaction relationships between V. natans and other species, and then affect the community dynamics of submerged vegetation.

Abstract:To reveal leaf nutrient use strategies of nitrogen-fixing leguminous trees (NLT) and non-nitrogen-fixing leguminous trees (n-NLT) under the nitrogen-rich environments in South China, five NLT (Pongamia pinnata, Acacia auriculiformis, Calliandra haematocephala, Ormosia pinnata, Acacia confuse) and three n-NLT (Sindora glabra, Saraca dives, Peltophorum tonkinense) were selected, the concentrations of carbon (C), nitrogen (N) and phosphorus (P) per leaf mass, leaf C: N and C: P, maximum net photosynthetic rate per leaf area (A_area), photosynthetic nitrogen use efficiency (PNUE) and photosynthetic phosphorous use efficiency (PPUE) were measured. The results showed that N and P contents and A_area of NLT were significantly higher than those of n-NLT, whereas their PNUE and PPUE had not significant difference. Although there was no significant difference in leaf C content between two types of species, leaf C: N and C: P of NLT were significantly lower than those of n-NLT. Therefore, these indicated that NLT in South China had stronger nutrient acquisition and photosynthetic capacity than N-NLT, but lower leaf nutrient utilization efficiency.

Abstract:In order to understand the differences of leaf functional traits of parasitic plants and their influencing factors, the effects of host plants on leaf functional traits of three mistletoes in Xishuangbanna were studied, and the correlation between leaf functional traits of mistletoes and host plants was analyzed. The results showed that there were significant differences in leaf functional traits of the same mistletoes from different host plants. The leaf water content (61.2%-70.1%), nitrogen concentration (9.6-16.0 g/kg), C/N (30.8-48.5), and condense tannin content (3.3%-11.0%) of Dendrophthoe pentandra displayed significant differences among its seven host species. Besides, the leaf water content (60.0%-71.7%), carbon concentration (431.3-502.3 g/kg), and condense tannin content (3.8%-9.9%) of Scurrula chingii var. yunnanensis also showed significant difference among its four host species, but there was no significant difference in functional traits of Helixanthera parasitica from its two host species. In general, leaf water content, carbon concentration, nitrogen concentration, C/N, and condense tannin content had positive significant correlation between mistletoes and their host plants. Therefore, it was concluded that host plants as nutrient resource could influence leaf functional traits of mistletoe. Mistletoe obtains water, carbon, nitrogen, and condense tannin from the host plant; but the ability to obtain different elements varies with host species.

Abstract:In order to explore the physiological and biochemical response patterns of Casuarina equisetifolia against infection of Ralstonia solanacearum, the disease-resistant assessment and selection of different C. equisetifolia families were studied based on the correlations between physiological and biochemical traits and disease-resistant characteristics. The results showed that the disease index (DI) and relative disease intensity (RDI) of 26 C. equisetifolia families were significantly different after inoculated with R. solanacearum. The differences of superoxide dismutase (SOD), catalase (CAT), phenylalanine ammonialyase (PAL), polyphenol oxidase (PPO), total phenolics (TP) and flavonoid (Flav) among the families were significant or very significant, indicating that the tested families had huge variation at resistance against R. solanacearum and great selection potential is expectable. The disease incidence and intensity of the 26 families presented negative correlation with the six physiological and biochemical indexes at significant or very significant level. It was indicated in a certain range that the more defense enzyme activities or secondary metabolite contents, the lower disease incidence and intension were detected. Two disease characteristics and six physiological and biochemical parameters were used to evaluate and select C. equisetifolia families against R. solanacearum, eight resistant families, including 201, 206, 198, 207, 202, 213, 208 and 195, were preliminarily selected according to the selection rate of 30%. The mean RDI and DI of eight resistant families were 25.94% and 28.93%, respectively, which was lower than those of overall mean values. And the activities of SOD, CAT, PAL, PPO, and contents of TP, Flav in these eight families were 11.90%, 13.50%, 24.77%, 12.71%, 25.68% and 18.76% higher than those of overall mean values, respectively. Therefore, the selected 8 families showed low disease degree, few wilting branches, and plant growth was not affected, indicating strong disease resistance and could be widely used in subsequent production.

Abstract:In order to obtain the information of terpenoids and their synthase genes of Cymbopogon citratus, the changes in the transcriptome and metabolome of young leaves under light and shade were studied, and the expression of terpenoid synthase genes was confirmed by qRT-PCR. Metabolomic analysis showed that C. citratus contained 23 terpenes, including 4 monoterpenes, 4 sesquiterpenes, 8 diterpenes, 3 triterpenes and 4 tetraterpenes. The relative contents of ginkgolide C and astaxanthin under shade was higher than those under light. According to transcriptome sequencing, there were 24, 49 and 58 genes encoding 4, 11 and 12 synthases involved monoterpene, diterpene and sesquiterpene and triterpene biosynthesis pathway, respectively, in which the relative expression of 8 genes encoding 6 synthetases significantly increased under shade, but that of premnaspirodiene oxygenase gene was just reverse. The expression patterns of four terpenoid synthase genes with significant difference FPKM values under shading by qRT-PCR was consistent with the transcriptome sequencing results, however, the differential expression of different synthase genes were different. Therefore, it was suggested that C. citratus contains 23 terpenoids in 4 categories catalyzed by 27 synthetases, which are encoded by 131 genes, and light intensity affects the relative content of 2 terpenoids and the expression of 9 synthetase genes.

Abstract:Ribonucleic acid interference (RNAi) is a biological process in which small RNAs regulate gene silencing at the transcriptional or post-transcriptional level. The argonaute (AGO) and dicer-like (DCL) proteins are two of the key components in the RNAi machinery of eukaryotes. In order to understand the function of AGO and DCL in sunflower (Helianthus annuus), the sequence of AGO and DCL in Arabidopsis thaliana were used for homology alignment in the sunflower database. The bioinformatics of AGO and DCL family members in sunflower were analysed. The results showed that there were 15 HaAGOs and 5 HaDCLs members obtained, which were unevenly distributed on chromosomes. The HaAGOs members could be cluster into 3 clades, containing conserved domains of N domain, DUF1785, PAZ and PIWI, whereas those of HaDCLs could be cluster into 4 clades, containing conserved domains of PAZ and RIBOc. The expressions of HaDCL3a and HaDCL3b in the steam and peduncle were stronger than those in other tissues. The subcellular localization showed that HaAGO was mostly localized in the nucleus. Therefore, it was suggested that a typical RNAi mechanism might exist in sunflower, and involve in coordinating growth and development in sunflower.

Abstract:In order to understand the effects of temperature and humidity stratification on seed content of Taxus chinensis var. mairei, the seeds were treated under four seasons and two humidity (16% and 24%) stratifications for 12 months, and then the changes in soluble sugar, starch, soluble protein and fat of seeds were studied. The results showed that the contents of seed storage substances changed significantly under different stratification treatments. The soluble protein content reached the highest after stratification for 9 months in spring, and the soluble sugar content showed a trend of decreasing-increasing-decreasing. Starch and fat contents decreased gradually with stratification. The starch content decreased the lowest after stratification for 9 months in autumn. Compared with the 24% humidity, the fat content decreased in the spring, autumn and winter after stratification for 9 months under 16% humidity, indicating that the metabolic activity of seeds was stronger under 16% humidity. The warm temperature in spring and autumn could promote seed metabolism and post-ripening. High temperature in summer caused the decrease of seed viability. After summer stratification for 3 months, the seeds had become moldy and rotten. In the stratification process, seed contents were degraded into soluble proteins and soluble sugars under the action of related enzymes, which provide material and energy for seed germination. Therefore, seed stratification time, temperature and humidity and their interactions could be used as regulators of seed contents.

Abstract:To excavate and accurately utilize Arachis hypogaea resources in Fujian, five geographical indication varieties with different phenotype and seed coat color, including 'Laifang', 'Yakouxiaoliuqiu', 'Zhukouxiaozi', 'Wenhenghongyi' and 'Yanghou', were collected. Their biological traits were described in details and the nutritional components, such as fatty acid, mineral element, vitamin E, and sterols were analyzed. The appearance characteristics and seed coat color of these peanut varieties were different. The main stem height or lateral branch length was negatively correlated with individual plant productivity. Contents of protein, fat, soluble sugar, dietary fiber, fatty acid, mineral elements and bioactive components in different peanut varieties were significantly different (P < 0.05). Among these, the contents of protein in 'Yakouxiaoliuqiu', fat, O/L value, vitamin E, and resveratrol in 'Zhukouxiaozi', Fe and phytosterol in 'Wenhenghongyi' was the highest, respectively. These results indicated that all five special peanuts accord with the grade 1 standards for direct consumption and grade 3 peanuts for oil, and have obvious local characteristics such as high iron contents.

Abstract:To study the chemical constituents of Garcinia xanthochymus leaves, nineteen compounds were obtained from its leaves by UPLC-QTOF-MS, including bioflavonoids, flavonoids and phloroglucinols. Five compounds were isolated from 80% methanol extract of leaves by chromatographic methods. On the basis of spectral data, they were identified as dihydrokaempferol (1), dulcisbiflavonoid A (2), bilobetin (3), mono-[2-(4-carboxy-phenoxycarbonyl)-vinyl] ester (4) and kaempferol (5). Compounds 1 and 2 were isolated from G. xanthochymus for the first time, while compounds 3 and 4 were isolated from genus Garcinia for the first time. Compounds 1 and 5 showed antioxidant activity with IC₅₀ of 146.8 and 39.0 μg/mL, respectively.

Abstract:To understand the alkaloidal constituents of Aconitum episcopale, an Aconitum species endemic to China, and their toxicity against rat cardiomyocyte H9c2 cells, ten diterpenoid alkaloids were extracted from its roots. Based on physical and chemical properties and spectral data, their structures were identified as yunaconitine (1), crassicauline A (2), vilmorrianine C (3), vilmorrianine A (4), forestine (5), falconeridine (6), 14-O-acetylsachaconitine (7), sachaconitine (8), chasmanine (9) and vilmotenitine A (10), were isolated and identified from A. episcopale roots. Compounds 5, 6 and 10 were isolated from this species for the first time. The median inhibition concentrations of compounds 1- 4, 6- 7 and 9- 10 on H9c2 cells ranged from 163.8 to 341.6 μg/mL, showing the alkaloids in A. episcopale had toxic effects on H9c2 cells.

Abstract:To clarify the chemical constituents and their biological activities of Eurya chinensis, eleven compounds were isolated from its MeOH extract by various column chromatography methods, and the anti-proliferative activity of compounds against human nasopharyngeal carcinoma cells (5-8F) were evaluated. Basis on spectral data, their structures were identified as isoastinlbin (1), 3,5,7-trihydroxychromone-3-O-α-L-arabino-pyranoside (2), 1-O-trans-cinnamoyl-β-D-glucopyranose (3), 2-(4-hydroxyphenyl)ethyl-6-O-(E)-cinnamoyl-β-D-glucopyranoside (4), eutigoside D (5), 6-O-coumaroyl-1-O-[2-(3,4-dihydroxyphenyl)ethyl]-β-D-glucopyranoside (6), eutigoside A (7), 2-(4-hydroxypheny)ethyl-[6-O-(E)-caffeoyl]-β-D-glucopyranoside (8), grayanoside A (9), 4-hydroxyphenylethyl-1-O-β-D-[6'-O-(4-hydroxybenzoyl)]-glucopyranoside (10), benzyl-4'-hydroxybenzoyl-3'-O-β-D-glucopyranoside (11). Compound 4 was isolated from natural resources for the first time, while the compounds 2- 4, 8- 11 were obtained from the genus Eurya for the first time. The compound 10 showed moderate inhibitory activity on the proliferation of 5-8F cells by MTT method.

Abstract:To compare appearance traits, nutrients and aroma characteristics of fruits of different Psidium guajava cultivars, the appearance and nutritional qualities of five guava cultivars ('Hongbaoshi', 'Fenhongmi', 'Xigua', 'Shuimi', local cultivar) were measured by national standard method, and the aroma components were determined by head space-gas chromatography-mass spectrometry (HS-GC-MS) technology. The results showed that there were significant differences in fruit appearance and nutrients among five cultivars. For 'Shuimi', the fruit shape index was the lowest with oblate fruit and the least seeds; the contents of sugars (total sugar, reducing sugar, sucrose, and etc.), sugar acid ratio, and total phenol were the highest; and the contents of fructose, V_C and total flavonoids ranked in second; while the contents of fat, crude fiber, ash and total acid were the lowest. The principal component analysis (PCA) showed that 'Shuimi' had the highest comprehensive score, so the edible quality was the best, Hexanal and caryophyllene were the characteristic aroma components of red pulp cultivars, and 3-hydroxy-2-butanone was the characteristic aroma component of white pulp cultivars.

Abstract:In order to study the anti-HIV protease activity and molecular docking mechanism of Sophora tonkinensis roots, the chemical constituents from roots were isolated by silica gel, MCI and Sephadex LH-20. HIV protease was used to screen the compounds against HIV in vitro, and molecular docking was used to preliminarily explore the binding mechanism between the active compounds and HIV-1 protease. The results showed that eight compounds were isolated from S. tonkinensis roots. Based on spectral data, their structures were identified as trifolirhizin (1), matrine (2), N-acetylnicotinamide (3), 2'-O-methyladenosine (4), calycosin-7-O-β-D-glucoside (5), roseoside (6), sophoranochromene (7), and ononin (8). Besides, two plasticizer derivatives were also obtained as bis(2-ethylhexyl)benzene-1,2-dicarboxylate (9) and disobutyl phthalate (10). The IC₅₀ values of compounds 1 and 2 are 13.2 and 38.6 μg/mL, respectively. Molecular docking showed that it had certain binding effect with HIV protease. Compounds 3- 5 were isolated from this plant for the first time, while compounds 1 and 2 exhibited moderate anti-HIV activities.

Abstract:To improve the comprehensive utilization of Kadsura coccinea resources, the differential and highly enriched metabolic components of root, stem and leaf were analyzed by using wide range of targeted metabolomics techniques. The results showed that there were 642, 650 and 619 metabolites identified from roots, stems and leaves, respectively, in which phenolic acids, lipids, flavonoids and organic acids were dominant in quantity. There were 566 and 650 common metabolites in leaves and roots, stems and roots, respectively, of which 442 and 393 were significantly different metabolites, mainly including phenolic acids, flavonoids and lipids. Moreover, these differentially metabolites were significantly enriched in pathways of phenylpropane biosynthesis, flavone and flavonol biosynthesis. The total and secondary metabolites abundances were in the order of leaf > root > stem. The accumulation of phenolic acids, flavonoids and lipids in leaves and phenolic acids in stems were significantly higher than those in roots; while the abundance of amino acids and their derivatives, terpenoids, lignans, coumarins and alkaloids were significantly up-regulated in roots. Therefore, there were a large number of common components in roots, stems and leaves of K. coccinea. Phenolic acids, flavonoids and lipids in leaves and stems were highly enriched, and several bioactive compounds, such as neochlorogenic acid, chlorogenic acid and quercetin, were highly abundant and have high utilization value.

Abstract:The fertile plants of Grimmia ulaandamana J. Muñoz, C. Feng, X.L. Bai & J. Kou were recently discovered in Inner Mongolia, China. The characteristics of mature sporophytes, as well as female and male plants were described. The capsule of sporophytes is longer than the arcuate seta, capsular surface with longitudinal wrinkle, epidermal cell wall of central capsule was thick, ring cells square or short rectangular, the opercle with beak. The peristome teeth had papillose and bifurcated at upper part, separated at base, the base of peristome teeth is lower than mouth of capsule. There is a layer of small cells between epidermal cells and peristome teeth, the trabeculae of capsular bones are strongly protruding about 1/3 of the base. Capsular cap base intact. The innermost female bracts are larger the leaves at stem. Grimmia ulaandamana had important morphological variation, the fertile plants could provide more evidence to distinguish from the most similar species G. elatior. The novel description and illustrations of sporophytes were presented, and the phylogenetic significance of sporophytes was discussed.

Abstract:Based on the methods of morphology, anatomy, chemistry and molecular, Phaeographis flavescens Dal-Forno & Eliasaro (Graphidaceae) is recorded as new to China. It is characterized by crustose thallus, surface pale yellowish green, dull, smooth; ascomata flexuose, branched, immersed in pseudostromata; the lirellae have a narrow, brown-black edge, with small lateral cracks; disc flat, black, with white pruina; hymenium colorless, paraphyses with branched tips; ascospores 8 per ascus, brown, with transverse septa, (4-)6 locular, 19-25.5 μm×6-7 μm, I+ wine-red. The species is found in Yunnan and Fujian provinces, and the study enriches our understanding of the Phaeographis composition and distribution in China.

Abstract:To protect the plant and ecosystem diversity of the coastal zone and islands along Beibu Gulf, Guangxi, the species composition, origin, life forms, invasion routes and damage status of alien invasive plants were analyzed by field investigation using quadrats and transect methods and literature data. The results showed that there were total 64 invasive plants, belonging to 28 families and 55 genera, in which, Asteraceae (15 species) were the most. Herbaceous plants were most with 48 species, accounting for 75.00%. The plants originated from America were the most with 49 species. The risk level of invasion could be divided into 5 grades, among which grade Ⅰ (serious hazards) had 8 species, accounting for 12.50%. The alien invasive plants of Beibu Gulf were similar to those from Guangxi, Guangdong, Hainan and South China in species composition, life forms and origin. There were more than 60% of invasive plants come from the Americas in Beibu Gulf and inland area of China-Vietnam border in Guangxi. So, it was speculated that there were two possible invasion routes in Guangxi: one was from Hainan, and the other was from China-Vietnam border. Although the total number of alien invasive plants in Beibu Gulf was smaller than that in Guangxi, the prevention and control of 8 alien invasive species of grade Ⅰ should be paid more attention.