Abstract:In order to reveal the ecological strategies of lianas in karst habitats, the leaf function traits and their relationships of nine woody lianas in Chenqi watershed of the Puding Karst Ecosystem Observation and Research Station of Chinese Academy of Sciences were studied. The results showed that six leaf functional traits, such as leaf area, leaf thickness, chlorophyll content, specific leaf area, leaf tissue density and leaf dry matter content, had varied in different degrees. The interspecific variation of traits ranged from 9.24% to 98.18%, while intraspecific variation from 0.64% to 39.71%. The intraspecific coefficient of variation of traits in deciduous plant was lower than that in evergreen plants. Compared with leaves of karst trees and shrubs, lianas had lower thickness, tissue density and higher area and dry matter content. There was close relationship among leaf functional traits in lianas. Specific leaf area had significant negative correlation with leaf tissue density and leaf dry matter content, and leaf tissue density had significant positive correlation with leaf dry matter content. Chlorophyll content had significant negative correlation with leaf dry matter content. Leaf thickness had significant positive correlation with chlorophyll content, and significant negative correlation with leaf tissue density. Except for leaf thickness, leaf area had significant correlation with other traits. Combined the leaf economic spectrum theory analysis, Vitis davidii var. davidii, Pueraria montana, and V. amurensis belonged to "quick-return type", and Akebia trifoliata and Rubus pinfaensis, Rosa cymosa and Millettia extensa belonged to "slow-return type". The functional differentiation of Rubus coreanus and Berchemia polyphylla was obvious, fall in between. Therefore, it was suggested that lianas adopt different adaptation strategies by weighing the relationship among leaf functional traits in order to adapt to the arid and barren karst environment.

Abstract:In order to understand the stability of mixed forest community of Casuarina equisetifolia and Dendrocalamus minor var. amoenus in the coastal windbreak of Dongshan Island, China, the inter-specific association and niche of the community was analyzed by using quadrat method. The results showed that there was no significant positive correlation among inter-specific associations as a whole (VR=1.72, W=20.625), indicating that the community was in an unstable dynamic succession state. Two species pairs; D. minor var. amoenus and Lantana camara, U. procumbens and C. equisetifolia had high association and co-occurrence (PC ≥ 0.7, OI ≥ 0.8, DI ≥ 0.8). The niche width of invasive plant L. camara was high, and the niche overlap with D. minor var. amoenus was high, showing high positive correlation, making the population in an unstable state. The habitats of the coastal windbreak was simple, and the habits of dominant species were similar, so there was a strong positive interspecific association between D. minor var. amoenus and other most species. Restricted by environmental resources, the strong positive association was related to the large niche width of species. The strong positive interspecific association of species pairs and the potential competitive advantage of alien species might be an important factor affecting the stability of the community.

Abstract:In order to understand the variation patterns of nutrient elements for the first-order roots of woody plants in subtropical evergreen broad-leaved forests, the carbon and nitrogen concentrations of the first-order roots of 89 tree species in Wanmu Forest Nature Reserve, Jian'ou, Fujian Province, were determined based on root order method. The results showed that the mean C, N concentrations in the first-order roots of 89 tree species were 433.9 and 13.7 mg/g, and C:N ratio was 36.7, which variation coefficients were 6.4%, 39.2% and 39.9%, respectively. There were significant differences in C concentration of the first-order roots among different leaf habits (such as evergreen and deciduous trees) and growth forms (including tree, semi-tree or shrub and shrub). However, there was no significant difference in N concentration and C:N ratio. The differences in C, N concentrations and C:N ratio of the first-order roots among six main families (Lauraceae, Fagaceae, Aquifoliaceae, Symplocaceae, Pentaphylacaceae and Elaeocarpaceae) were significant. The N concentration of first-order roots increased with the phylogeny level from low to high. Therefore, it was indicated that the interspecific variation of the first-order roots in C concentration was lower than N concentration in the subtropical evergreen broad-leaved forest, the N concentration of the first-order roots was influenced by phylogeny, however, the concentration of C was affected by leaf habits and growth forms, showing a certain convergence effect.

Abstract:In order to reveal the enzymatic mechanism of soil nutrient transformation, the soil nutrient contents and enzyme activities in plantations, such as nitrogen-fixing tree species (Acacia crassicarpa, A. melanoxylon, A. cincinnata, A. auriculiformis, A. mangium) and non-nitrogen-fixing species (Eucalyptus urophylla×E. grandis) were studied, and their relationships were analyzed. The results showed that the pH in 40-60 cm soil of Acacia plantations were higher than that in E. urophylla×E. grandis plantation, which total P and K contents at all soil layers were lower than those in E. urophylla×E. grandis plantation, while total C and total N contents at 20-40 cm soil were high in Acacia plantations. Soil available nutrients contents were significantly higher in A. melanoxylon and A. mangium than those in E. urophylla×E. grandis plantation (P<0.05). Compared to E. urophylla×E. grandis plantation, the acid phosphatase and cellulase activities at 0-10 cm soil layer were high in Acacia plantations, which the activities of soil urease, sucrase, cellulase and aryl sulfatase were the highest in A. auriculiformis plantation (P<0.05); the activities of soil urease, cellulose, chitinase and amylase were the highest in A. cincinnata plantation (P<0.05). Correlation analysis revealed that the activities of soil urease, sucrase and chitinase were significantly negative to soil AP (P<0.05); the activities of soil sucrase and cellulase were signifi-cantly negative to soil NH₄⁺-N; the activities of soil urease, cellulase and aryl sulfatase were significantly negative to soil TK; the activities of soil chitinase were significantly positively to soil TN; the activities of soil amylase were significantly positively to soil NH₄⁺-N; the activities of soil catalase were significantly positively to soil TK. Therefore, compared to E. urophylla×E. grandis plantation, the introduced Acacia species to soil degraded mountains in southern China could improve key soil enzyme activities and soil available nutrients, which was beneficial to the eco-restoration of degraded soil and the maintenance of long-term productivity of plantations.

Abstract:In order to understand the community structure of Castanopsis hystrix and Acacia mangium broad-leaved mixed forest in Longyandong Forest Farm in Guangzhou, its species diversity was analyzed. The results showed that the species richness was in the order of tree layer > shrub layer > herb layer > interlayer plant layer. The Simpson and Shannon-Wiener indices of tree layer were 0.945 and 0.237, respectively, with the density of 2 671 ind./hm². Castanopsis hystrix, A. mangium, Melicope pteleifolia, Triadica cochinchinensis and Acacia confusa had high importance values of 12.79%, 10.98%, 8.08%, 7.78% and 7.02%, respectively. Among the 35 shrub species, the important values of Litsea rotundifolia var. oblongifolia (14.95%), Psychotria asiatica (12.60%) and Cratoxylum cochinchinense (10.17%) were more than 10%. The dominant family of interlayer speciess was Rubiaceae, followed by Apopynaceae. The density of herb species was about 38 000 ind./hm², and Poaceae was the dominant family, which consists of 9 species. Castanopsis hystrix community was transited from young age to middle age, the dominant population was growth type, while Acacia mangium community was transited from near maturity age or mature age to over maturity age. Compared with similar forests in different region, the biodiversity of mixed forest was much higher than that of pure forest. Therefore, C. hystrix-A. mangium broad-leaved mixed forest had formed the structure of mixed multilayer and different age forest with high species richness in tree layer, shrub layer and herb layer.

Abstract:In order to explore the variability of leaf characters and growth traits among different families of Michelia chapensis, the leaf morphology, growth indexes and their correlations of 15 families were analyzed. The results showed that there were significant differences in leaf characters among M. chapensis families. The coefficient of variation (CV) of leaf characters in Maozifeng family was the largest (23.55%) among 15 families, and that in lejiu5 family was the smallest (12.63%). Among seven leaf characters, the CV of dry matter mass was the largest (25.50%), and that of petiole length-width ratio was the smallest (5.14%). The variation of crown density, DBH and tree height (H) within families was more significant than that between families. The correlation analysis showed that leaf length had significant positive correlation with leaf width (P<0.05), as well as the correlation between leaf dry matter mass and leaf area. According to cluster analysis, 15 families could be divided into 4 categories. The families in category I had dense crown and tall tree, those in categories II and III had sparse crown and short tree, and those in category IV had sparse crown but tall tree. Therefore, these would provide a theoretical basis for the rational development and utilization of M. chapensis.

Abstract:In order to explore the cold resistance of Hedychium species and select the cold-tolerance species, the changes in relative conductivity, contents of soluble protein and malondialdehyde (MDA), activities of superoxide dismutase (SOD) and peroxidase (POD) of 3 species and 11 cultivars of Hedychium were studied under natural overwintering condition and then their cold resistance were comprehensively evaluated by principal component analysis combined with subordinate function method. The results showed that the five physiological indexes increased at first and then decreased along the winter, and most of them reached the maximum value in the coldest month (February). In the same period, the species or varieties with strong cold resistance had low relative conductivity and MDA content, and high activities of SOD and POD, as well as soluble protein content. The correlation analysis showed that SOD activity was significantly negatively correlated with MDA content, and soluble protein content was extremely significantly positively correlated. MDA content and soluble protein were significantly negatively correlated. Principal component analysis showed that the five indicators could be converted into two principal components, with a cumulative contribution rate of 81.29%. The decreased order of cold resistance of Hedychium germplasm and cultivars by comprehensive evaluation was H. ‘Orange Crush’, H. coccineum var. aurantiacum ‘Orange Brush’, H. ‘Clown Suit’, H. chrysoleucum, H. coronarium, H. gardnerianum ‘Kahili’, H. coronarium ‘Elizabeth’, H. ‘Pink V’, H. flavescens, H. gardnerianum ‘Tara’, H. ‘Tarissima’, H. ‘Fireflies’, H. stenopetalum ‘White Stars’, and H. coronarium ‘White Starburst’. Therefore, these would provide theoretical and practical basis for the selection of excellent cold-resistant species of Hedychium and the promotion and application of variety resources.

Abstract:In order to establish a comprehensive evaluation system for cold resistance of Manglietia species, the key physiological indexes of cold tolerance in seven cutting seeding were determined under low temperature. The fitting logistic equation was used to calculate the semi-lethal temperature of low temperature (LT₅₀), and the key indexes of cold resistance were screened and evaluated by membership function method. The results showed that the LT₅₀ of seven Manglietia species were in the order of M. fordiana < M. insignis < M. nucifera < M. patun-gensis < M. conifer < M. paruicula < M. crassipes, which had positively significant correlation with relative conductivity. With the temperature decrease, the contents of free proline and soluble protein, activities of superoxide dismutase and superoxide dismutase in seven Manglietia species fall after rising, while contents of soluble sugar and malondialdehyde increasing and gradually leveling off. The cluster analysis showed that 7 Manglietia species could be divided into 3 groups, cold resistance of Manglietia fordiana and M. insignis were stronger, M. nucifera, M. patungensis and M. conifera were medium, M. paruicula and M. crassipes were weak.

Abstract:To regulate planting and increase yield of Peucedanum praerupterum, the photosynthetic and fluorescence characteristics were studied under different shading, such as full sunlight (CK) and shading 20%, 40%, 60%. The results showed that the maximum electron transfer rate was 247.129 and 266.866 μmol/(m²·s) under CK and shading 20%, with maximum net photosynthetic rate of 25.621 and 28.167 μmol/(m²·s), respectively, which were significantly higher than that of shading 40% and 60% (P<0.05). The saturated light intensity corresponded to the maximum net photosynthetic rate under CK and shading 20% were 2 130.419 and 1 927.804 μmol/(m²·s), respectively, which were significantly higher than those under shading 40% and 60%. The light energy use efficiency and water use efficiency of P. praerupterum leaves had differences among different shading treatments, while the photochemical quenching coefficient and non-photochemical quenching coefficient had no significant difference. Therefore, it was suggested that P. praerupterum was a typical heliophyte with strong adaptability, so that it was beneficial to choose the open field with sufficient light intensity for the cultivation of P. praerupterum.

Abstract:In order to understand the genetic diversity of Archidendron clypearia germplasms resources, the genetic diversity and relatedness of 146 individuals from 12 wild populations in Guangdong Province were studied by using SSR molecular marker technology. The results showed that a total of 249 alleles were detected by 21 pairs of SSR primers with an average alleles (Na) of 11.857, the effective number of alleles (Ne) of 3.500, as well as expected heterozygosity (He) of 0.718, and polymorphism information content (PIC) of 0.676. The Shannon diversity index (I=0.528) and effective number of alleles (Ne=0.716) of Boluo population were the highest among 12 populations, which is the most genetically diverse population. The coefficient of genetic differentiation among populations was 0.071, and the genetic variation of A. clypearia was mainly within populations (97%), and the genetic differentiation within populations was greater than that among populations. Meanwhile, the cluster analysis showed that the 12 populations could be divided into 6 types according to genetic coefficient of 0.16, which was similar to that of principal coordinate analysis. So, these would provide an important theoretical basis for the exploitation, utilization, and protection of A. clypearia germplasm resources, and genetic breeding of fine variety.

Abstract:In order to explore the causes of the endangered species Horsfieldia hainanensis, the genetic diversity and population structure were analyzed by using restriction-site associated DNA sequencing (RAD-seq) for developing single nucleotide polymorphisms (SNPs). The results showed that the genetic diversity of H. hainanensis was low (Ho=0.167) and the genetic differentiation between populations was significant (F_st=0.120). Structure analysis showed that the optimal clustering value of the population was 2, but the genetic structure of some populations was mixed, which was consistent with the results of Mantel correlation test showing no correlation between genetic distance and geographic distance (r=0.733, P<0.075). Therefore, low regeneration ability and excessive disturbance of human activities might be the main reason for endangered status of H. hainanensis. It was recommended to strengthen in situ conservation of populations with high genetic diversity, such as BWL and YGL, and strengthen near-situ or ex-situ conservation of populations with severe habitat damage, such as EXL and DLS, to increase gene exchange among populations. At the same time construct the core germplasm of this species to prevent the aggravation of genetic resource loss.

Abstract:In order to understand the chemical constituents of bran shell of Coix lachryma-jobi, fifteen compounds were isolated from ethyl acetate fraction of ethanol extract by using various chromatographic methods. Based on their spectroscopic data, their structures were isolated as p-coumaric acid (1), p-coumaric acid methyl ester (2), (E)-2-hydroxyethyl-3-(4-hydroxyphenyl) acrylate (3), caffeic acid methyl ester (4), methyl (E)-3-(4-hydroxy-3-methoxyphenyl) acrylate (5), (E)-3-(4-methoxyphenyl)acrylic acid (6), 2,3-dihydroxy-1-(4-hydroxy-3-methoxyphenyl)propan-1-one (7), 2,3-dihydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl)-1-propanone (8), p-hydro-xybenzoic acid (9), 3-hydroxy-4-methoxybenzoic acid (10), 1,3,5-trimethoxybenzene (11), methyl (3-hydroxy-2-oxo-2,3-dihydroindol-3-yl)-acetate (12), allantoin (13), 2-(2-hydroxyethyl)-3-methylfumaric acid (14) and 9-octadecenoic acid (15). The compounds 3, 7, 12, 13 and 14 were isolated from coix for the first time. The compounds 1, 2, 9, 10 and 11 had significant inhibitory activity on seed germination.

Abstract:To study the separation and purification of polyphenols from Myrciaria cauliflora leaves, four resins, such as NKA-2, NKA-9, HPD-826 and HPD-400A, were screened, and the antioxidant, in vitro hypoglycemic activities and components of polyphenols were analyzed. The results showed that NKA-9 resin was suitable for the purification of polyphenols from the leaves. The optimum conditions were as follows:sample concentration of 2.00 mg/mL, flow rate at 1.0 mg/mL and sample loading of 204 mL, 70 mL 70% (V/V) ethanol as elution with velocity at 0.9 mL/min. Under the conditions, the purity of polyphenols from the leaves could reach 69.86%. The antioxidant and α-glucosidase inhibitory activities of purified polyphenols from leaves of M. cauliflora were stronger than those of crude polyphenols, but the inhibitory activities on α-amylase were lower. According to HPLC, the monophenols in leaves of M. cauliflora contained myricetin, rutin, hyperoside and ellagic acid, and ellagic acid content was highest with (16.15±0.49) mg/g. Therefore, NKA-9 resin was suitable for separation and purification of polyphenols from leaves of M. cauliflora, the antioxidant and α-glucosidase inhibitory activities of purified polyphenols increased.

Abstract:To investigate the chemical constituents of Dalbergia cochinchinensi, five neoflavonoids and seven other compounds were isolated from its heartwood by various methods, such as organic solvent extraction, fractionation and chromatographic separation techniques. Based on physical and chemical properties and spectral data, their structures were identified as 7-hydroxy-2',3',4'-trimethoxyisoflavan (1), 6,4'-dihydroxy-7-methoxy-flavan (2), R-dalbergiphenol (3), R-4-methoxydalbergione (4), mimosifoliol (5), R-5-O-methyllatifolin (6), R-latifolin (7), maackiain (8), secundiflorol Ι (9), 3,9-dimethoxy-6H-benzofufo[3,2-c]chromen-6-one (10), muco-dianin C (11), lup-(20)29-ene-2α,3α-diol (12). Compounds 1, 5 and 8-12 were isolated from D. cochinchinensi for the first time.