Abstract:Considering the unique geographical conditions (serious soil wind erosion, salinization, desertification and soil water erosion) and extreme climate index (extreme high/low temperature days and extreme precipitation days) in the semi-arid desert and steppe ecological zone of northern China, an evaluation system for the ecological vulnerability was established by introducing the large-scale landscape pattern indexes (Shannon uniformity index and contagion index). Then, the spatial and temporal changes in the ecological vulnerability during the last 13 years were analyzed and discussed. The results showed that the ecological vulnerability over the semi-arid desert and steppe ecological zone of northern China belonged to moderate vulnerability, and showed a decreasing trend from west to east. During 2000-2013, there was a decreasing change trend in ecological vulnerability. In the last 13 years, the temporal and spatial patterns of ecological vulnerability of the semi-arid desert and steppe ecological zone of northern China were significantly affected by GDP density, temperature, precipitation and topography factors. All of these would provide scientific supports for environmental modification and protection in the semi-arid desert and steppe ecological zone of northern China.

Abstract:In order to understand the regeneration ability of Dacrydium pierrei under nature condition, the seed rain, soil seed bank and seedlings and saplings of D. pierrei at Bawangling, Hainan, China were observed for 3 years, and the relationship between environmental factors and the number of seedlings and saplings was analyzed. The results showed that the effective seeds number of seed rain and seed bank of D. pierrei was very litter and had seasonal differences. There was an on-and-off-year phenomenon of fruiting in population. The dispersal density of seed rain gradually decreased with the increment of distance to mother tree. The seed number of soil seed bank in the litter layer accounted for the largest proportion, but the viable seed number was small. The suitable altitude range for seedlings and saplings was from 800 to 1 400 m, and the longitude, latitude, slope had significant correlation with the distribution of seedlings and saplings. Therefore, artificial managements, such as picking seeds in suitable season, improve the quality and quantity of seed sources, and removing litter under forest, enhance seed germination ability, should be considered appropriately for D. pierrei regeneration.

Abstract:In order to clear the potential distribution region of rare plant Camellia nitidissima, the Maxent model was used to simulate the potential suitable habitats of C. nitidissima in China based on its distribution data as well as combined with climate, elevation, land use types and other environmental data, and then it was verified by using the ROC curve analysis method. The results showed that the suitable growth area of C. nitidissima was mainly located in the southwest areas of China, which is coincident with the known native sites, but not limited to sites already reported. The AUC area was 0.992 by using ROC curve, indicating that the predicting results were reliability. The major environmental factors affected C. nitidissima distribution (threshold) by Jackknife test included the annual average temperature (24.3℃), accumulated temperature (7 515.84℃), humidity in the driest season (14.5%), and average temperature in the wettest season (26.2℃). The disturbance of human activities to the habitat of C. nitidissima was evaluated quantitatively by Buffer analysis. All of these would be helpful for setting out conservation planning of C. nitidissima.

Abstract:In order to understand the resistance of Morinda citrifolia, its eco-physiological characteristics were studied grown in Dongdao of Xisha Islands, China. The results showed that M. citrifolia was a heliophyte with strong competitive ability for light resources. The contents of N, P and chlorophyll b were high in leaves, which was an important character in adaptation to tropical costal island habitat. M. citrifolia had big sponge tissue and stoma density with small vessel diameter. The content of malondialdehyde, activities of superoxide dismutase and catalase were high with low proline content, which indicated that M. citrifolia had strong drought resistance. In addition, N content in soil was low with high salt content. So, M. citrifolia could be used as one of the tool species in the vegetation restoration in tropical coast.

Abstract:In order to understand the eco-physiological characters of Terminalia catappa, its leaf morphology, physiology, nutrient element contents and the rhizosphere soil characteristics were studied grown in Yongxing Island, Xisha Islands. The results showed that T. catappa had low specific leaf area, thick leaf thickness and low stomatal density. The chlorophyll a/b (2.25:1) was lower than theoretic value (3:1). The SOD and POD activities in leaves were low, but proline and abscisic acid contents were high. The nutrient element contents in leaves were high, but the suitable soil nutrient content was low. It indicated that the leaves of T. catappa had high light energy absorptivity, good water holding capacity, and high drought tolerance, thus it was suitable to grow in poor soil conditions and maintain high leaf nutrition levels. Overall, T. catappa can tolerate high temperature, drought and barren soil and can be used as a tool and landscaping species for vegetation restoration on tropical coral island.

Abstract:In order to select the superior provenances/families of Litsea cubeba at seedling stage, the genetic variations of seedling height (h) and base diameter (bd) of 13 provenances and 55 families were studied. The results showed that the growth period of 1-year-old seedings of L. cubeba could be divided into three stages, including initial growing stage, fast growing stage and full lignification stage. The growth peak of base diameter was earlier than that of seedling height. The increment of seedling height and ground diameter were different significantly among 13 provenances and 55 families (P<0.01). Through comprehensive selection index method, the comprehensive selection formula was established as I=0.007X_h+0.74X_bd. The five families, including Jianyang 2, Fuyang1, Suichuan 8, Suichuan 13 and Anhui 1, were selected as level I with a selection rate of 9.1%. The expected genetic gains of seedling height and ground diameter of Zhejiang Fuyang and Fujian Jitneying provenances were the highest. Meanwhile, those of seven families, including Jianyang 2, Suichuan 8, Fuyang 1, Suichuan 13, Anhui 1, Jianyang 3, Anhui 6 were the highest. Therefore, based on multi-trait comprehensive selection and genetic gain values, the five families (Jianyang 2, Fuyang1, Suichuan 8, Suichuan 13 and Anhui 1) and two provenances (Zhejiang Fuyang and Fujian Jianyang) were evaluated as superior provenances/families.

Abstract:In order to screen fungi with promoting effect on Artemisia annua growth, the endophytic fungi were isolated from A. annua brunches by tissue isolation method and molecular identified. The promoting effect of Trichoderma atroviride was studied. The results showed that 23 endophytic fungi were isolated belonging to 16 speices, in which the genus Colletotrichum was dominant. The fermentation broth of T. atroviride had significantly negative effect on seed germination and seedling growth of A. annua The mycelium of T. atroviride liquid fermentation had significant promoting effect on seedling growth of A. annua during April to May, but did not after July. So, it was suggested that T. atroviride could be used as fertilizer for seedlings of A. annua, and it combining with chemical fertilizer could also be applied to adult plants.

Abstract:In order to selective breeding and seedling production of Dendrobium officinale, the pollination success rate, fruit-set rate and seed germination rate of 46 germplasms were studied by using artificial pollination, including autogamy, geitonogamy, crossing among different plants within the same germplasm and crossing among different germplasms. The results showed that the pollination was successful by crossing between different germplasms, and the fruit setting rate were high. While there were only 31.3% germplasms successful by self-pollination, and the fruit setting rate had markedly difference. The pollination success rate and fruit setting rate of geitonogamy and crossing among different plants within the same germplasm were both intervenient. And the same changes were observed in seed germination rate and speed as well as the fruit setting rate among 4 types of pollinations. These indicated that self-incompatibility existed in D. officinale germplasms, so that the pollination success rate, fruit setting rate and seed germination rate could increase markedly by crossing between different germplasms.

Abstract:In order to understand the effects of Zn, B fertilization on flavonoids accumulation in Spatholobus suberectus Dunn., the changes in contents of flavonoid and soluble protein, PAL activity were studied by using foliage spray. The results showed that the soluble protein content, PAL activity and total flavones content of S. suberectus increased spraying Zn, B fertilization. The soluble protein content was the highest for 0.89% treated with 50 mg L^-1 ZnSO₄ +10 mg L^-1 Na₂B₄O₇·10H₂O. The total flavones content and PAL activity were the highest, for 4.65% and 29.47 U g^-1 min^-1, respectively, when S. suberectus were treated with 25 mg L^-1 ZnSO₄+50 mg L^-1 Na₂B₄O₇·10H₂O. Therefore, reasonabe fertilization of Zn, B could promote the accumulation of flavonoids in S. suberectus.

Abstract:Sciaphila nana, a species representing a new familial record of flora of Myanmar, is described and illustrated. Sciaphila nana is characterized by having monoecious plants, flowers with six tepals, inner tepals of male flowers having knob tip, three stamens, and stamen 4-celled.

Abstract:Hoya tamdaoensis Rodda & T. B. Tran is reported as a newly recorded species to China. The species is currently known from Napo County, Guangxi Province, growing in limestone evergreen broad-leaved forest. We provide description of the species, supplementary description of fruits and seeds that were absent when published in the paper. Photos of the species are also provided for identification. The voucher specimens are stored in Herbarium of Guangxi Botanical Garden of Medicinal Plants (GXMG).

Abstract:In order to understand the nematicidal activities of amide alkaloids from the seeds of Clausena lansium, ten amide alkaloids were isolated by comprehensive chromatographic techniques. On the basis of spectral data, their structures were identified as:N-methyl-cinnamamide (1), clausenalansamide A (2), 3-dehydroxy-3-methoxyl-clausenalansamide A (3), clausenalansamide B (4), lansiumamide B (5), N-2-phenylethyl-cinnamamide (6), 2'-dehydroxy-2'-oxo-clausenalansamide B (7), lansamide-7 (8), homoclausenamide (9), 1,5-dihydro-5-hydroxy-1-methyl-3,5-diphenyl-2H-pyrrol-2-one (10). Among them, compounds 3, 7 and 10 were new natural products. Meanwhile, the nematicidal activity against Panagrellus redivivusl was tested for the first time. All of them showed the nematicidal activity, and compounds 2, 3, 5 and 8 presented stronger activities than dichlorofenthion, providing scientific evidence for the development of new pesticide.

Abstract:Epiphytes are special plant groups live on other plants or residues. Most of epiphytes grow in the canopy and far from the ground soil in the space, there are obvious limitations in the absorption of light, water and nutrients. The taxa, distribution, ecological function and adaptability to the environment of epiphytes were reviewed, and the reasons of its vigorous growth in habitat environment with limited resources and occupy the important niche were mainly analyzed. The future researches was prospected, such as update epiphytic database, make certain the sources and use strategies of water and nutrient, strengthen researches on exploitation and utilization and resource restoration and reconstruction.