Abstract:In order to understand the relationship between tree structure and its function, the vessel characters of sap wood of eight tree species, Acacia auriculaeformis, Schima superba, Michelia macclurei, Castanopsis hystrix, C. fissa, A. mangium, Eucalyptus citriodora and E. urophylla×E. grandis and their stem sap flux densities in wet and dry season monitored by using Granier's thermal dissipation probe method, were investigated in subtropical south China. The results showed that vessels were of single-type in these tree species except for M. macclurei that had two types of vessels. The vessel length, density and lumen diameter were significantly different among the eight tree species, and obvious relationships among the three vessel characters were observed. The normalized area of sap wood had significant relation with the vessel characters. No significant relation of the maximum sap flow with vessel characters was found, but it existed between the maximum whole tree transpiration rate and the vessel characters in wet season, and so did that of the daily total transpired amount with the vessel characters. Therefore, the vessel in trunk had no influence on sap flow rate, the negative trade-off relation between vessel diameter and sapwood area of trunk could the difference in water transpiration rate of trunk caused by the difference of vessel diameter of the tree species.

Abstract:In order to understand the effects of precipitation pattern on litter-fall in lower subtropical evergreen broad-leaved forest, a field precipitation manipulation experiment at Heshan National Forest Research Station (Guangdong Province, China) was designed to simulate decreasing dry-season (October-March) and spring (April-May) rainfall and the litter-fall respones in the forest was studied. The results showed that annual litter-fall of the experimental forest was 9.24 t hm^-2, of which leaf litter was the main composition at different stages, accounting for 50.7%-69.3% of the total. The decreasing dry-season rainfall (DD) treatment significantly reduced leaf litter production (P<0.01). The whole-year litter production was also reduced by 10.3% under the DD treatment compared to the control, but not statistically significant. Decreasing spring rainfall (ED) also reduced flower-, fruit-, and leaf-litter as well as the total during the spring time, but the whole-year litter production was increased by 11.3% compared to the control. No statistically significant difference of ED effects on the spring and wholeyear litter production was found. Neither DD nor ED treatments had obvious impacts on the quality of leaf litter, but DD treatment significantly reduced lignin content in leaf litter of Michelia macclurei (P<0.05). Therefore, the changes in precipitation pattern could influence the soil carbon sink in the lower subtropical forests of China.

Abstract:In order to understand the landscape restoration of landfill in Big Taipa Hill, Macau, the species composition, vertical structure, floristic components, and community appearance were investigated by using sampling method. The results showed that there were 83 vascular plants in 12 plots of 1200 m². The floristic composition of the community was dominated by Pantropical genera, account for 38.98%. The community appearance was determined by the micro- and meso-phanerophyte with herbaceous, simple and micromonophylls. The indexes of the landfill community were similar to that of nature plant community, indicated that the restoration of landfill was good. Based on the current situation of landfill, some preferred species for landscape restoration were selected, and suggestions were given for improving landscape. It was recommended that the landscape restoration should be carried out in stages. To get faster and better landscape restoration, proper manual intervention should be taken at different stages of community succession.

Abstract:In order to determine the stoichiometric traits of two fern species and their relationships to soil available nutrient, the above-and belowground parts of Dicranopteris dichotoma and Blechnum orientale and soils at 0-10 cm and 10-20 cm layers were collected from subtropical forests in Fujian Province, respectively. The carbon (C), nitrogen (N) and phosphorus (P) contents in plant and soil were measured. The results showed that N and P contents were significantly higher in aboveground than those in belowground, while C content did not show significant difference, which led to lower C:N and C:P ratios in aboveground. Compared with B. orientale, D. dichotoma had low N and P contents in aboveground; high C content, C:N and C:P ratios in both above-and belowground; high coefficient of variation and phenotypic plasticity indices of N and P contents. These stoichiometric trends may indicate that D. dichotoma had high nutrient use efficiency by maximizing its performance, while B. orientale had low nutrient use efficiency by sustaining its performance. N contents in both of the above-and belowground of two fern species were not significantly correlated with available N in soil at depth from 0 to 20 cm. Total P content in soil (both in 0-10 cm and 10-20 cm layers), however, was significantly and positively correlated with the P contents in both parts of D. dichotoma, but not with those in B. orientale (only P content in belowground had weak positive correlation with total P content in soil of 10-20 cm layer. Therefore, it was suggested that D. dichotoma could be a potential indicator of soil P availability in subtropical forests.

Abstract:The objective was to understand the effect of fluoride (F) stress on chlorophyll fluorescence in tea [Camellia sinensis (L.) O. Kuntze ‘Ruixiang’] leaves. Tea seedlings at 10-month-old grown in pots were fertilized with NaF three times weekly for 6 weeks. The results showed that O phase in OJIP curve rose a little treated with 600 mg L^-1 NaF, and P phase and IP phase decreased obviously, L-step at about 150 μs and K-step at about 300 μs appeared. Under F stress, the fluorescence parameters, such as RC/CS_o, ET_o/ABS, RE_o/ET_o, RE_o/ABS, PI_abs and PI_cs decreased in tea leaves, while V_J, V_I, DI_o/RC, DI_o/CS_o, DI_o/ABS and dissipated energy increased. There were negative correlations between F content in tea leaves and ET_o/TR_o, RE_o/ABS and PI_CS, but a positive correlation with DI_o/RC. Therefore, the ability of photosynthetic electron transfer in tea leaves was weakened under F stress, the whole electron transport chain from PSII to PSI was affected, meanwhile, leaves could prevent light suppression and light damage by increasing heat dissipation itself.

Abstract:In order to understand the effect of cultivated environment on nutrient components in leaves of Gnetum montanum Markgr. f. megalocarpa Markgr., its seeds were collected in Jingdong County, Yunnan Province, and the seedlings were cultured in greenhouse in Beijing and Kunming, respectively, the nutrient components of oneyear-old seedlings leaves were studied. The results showed that the most of nutrient components in leaves of G. montanum f. megalocarpa had no significant differences between two cultivated environments. The contents of total starch, total sugar, flavonoids and alkaloids had no significant differences, while there were significant differences in nutrient constituents, such as disaccharide, kaempferol, amino acid and macronutrients. The most of element contents in leaves were affected significantly by those in soils. Therefore, different habitats had slight effect on the nutrient constituents in leaves of G. montanum f. megalocarpa.

Abstract:The aim was to comprehensive evaluate the parents of F₂ (BC₁) generation from Saccharum spontaneum ‘Yunnan 82-114’, sixty-five parent materials were screened by similarity-difference analysis based on conjugated aggregation theory. The results showed that the materials occupied top 10 similarity-difference correlation degree were Yunrui09-23 (YR09-23), Yunrui09-44, Yunrui09-36, Yunrui09-74, Yunrui09-65, Yunrui09-35, Yunrui09-14, Yunrui09-58, Yunrui09-51 and Yunrui09-67. There were thirty-three and thirty-six materials exceeding control variety Xintaitang22 (ROC22) and Yuetang93-159 (YT93-159), respectively. The 65 parent materials could be classified twenty-six clusters in equivalence matrix (λ=0.910). The parents with front rank of similarity-difference correlation degree and different clusters usually have some outstanding characters. These would provide the basis for selecting and utilizing parent materials.

Abstract:In order to understand the genetic diversity of local pear (Pyrus spp.) in Guizhou Province, thirtyfour germplasms were collected and their fruit qualities were observed for three years. Twelve indicators of fruit quality were analyzed using principal component analysis (PCP) and Q-type cluster methods. The results showed that there was significant difference among the 34 pear germplasms in all fruit quality traits except for edible rate, demonstrating that pear germplasm resources in Guizhou have abundant genetic diversity. The principal component analysis showed that the first five principal components accounted for 85.52%, respectively, indicating that the contribution rate of fruit quality characters scattered and cumulative contribution rate was not obvious, and at the same time showing that the variation of fruit qualities of pear resources have pleiotropy. Q-type cluster analysis showed that Haizi pear-3 and Hulu pear cluster each, which revealed their unique quality characteristics. These would laid foundation for development and utilization and variety selection of pear germplasm resources in Guizhou Province.

Abstract:In order to understand the response of sweet potato (Dioscorea esculenta) to Ralstonia solanacearum, two varieties, including resistant ‘Xiangshu 75-55' and sensitive ‘Shenglibaihao’, were used as materials, the changes in photosynthetic characteristics, abscisic acid (ABA) content and chloroplast ultrastructure were studied after infected by R. solanacearum. The results showed that the membrane permeability (MP), intercellular CO₂ concentration (Ci) and endogenous ABA content in ‘Shenglibaihao’ infected by R. solanacearum increased markedly, but chlorophyll (Chl) content, net photosynthetic rate (Pn), transpiration rate (Tr) and stomatal conductance (Gs) obviously decreased. Besides, the integrity of chloroplast membrane system was damaged, the number of chloroplast decreased, and expansion to collapse, the grana lamella loosed and disintegrated, and starch grains got smaller in ‘Shenglibaihao’ leaves affected. In contrast, for ‘Xiangshu 75-55', the changes in the related physiological indexes were not different significantly, and the plasma membrane and lamellar still kept integration. Therefore, there were distinct differences in the PMP, Chl content, ABA content, Pn and chloroplast structure between the two sweet potato varieties with different disease-resistance.

Abstract:In order to understand the genetic relationship of Morinda citrifolia (noni), the DNA fingerprints of 13 noni germplasm resources of were studied by ISSR markers. The results showed that ten ISSR primers could amplify 183 bands, of which 159 bands were polymorphic, accounting for 86.9%. The genetic similarity coefficients of 13 noni germplasm resources ranged from 0.464 to 0.784. Cluster analysis showed that 13 noni germplasm resources could be divided into two clads, in which Small fruit as a single group had distant relation with other germplasm resources. Although all noni germplasm resources could not completely separated according external morphological characteristics, the most with the same characteristics could be clustered into the same group or sub-group.

Abstract:Examinations of literatures and specimens in herbaria have shown that three Chinese species of the genus Cladrastis Raf. (Leguminosae), viz. C. parvifolia C. Y. Ma, C. scandens C. Y. Ma and C. chingii Duley & Vincent, are conspecific with C. platycarpa (Maxim.) Makino, a species distributed widely in China and Japan. C. parvifolia is here treated as a variety, namely C. platycarpa var. parvifolia (C. Y. Ma) Z. Q. Song, D. X. Xu & S. J. Li, comb. et stat. nov., while C. scandens and C. chingii are reduced to new synonyms of C. platycarpa. Finally, The taxonomic position and the geographic dispersal of the speices were discussed.

Abstract:Bamboo species (Poaceae: Bambusoideae) possess a distinct life history characterized by a predominance of rhizome-dependent asexual reproduction and erratic flowering at intervals of 1 year to 120 years. Some bamboo species are of notable economic, ecological and social significance throughout the World. Considerable progress has been made in bamboo research in the past few years. The advances in bamboo molecular biology since 2003 were reviewed, including the development and application of modern molecular tools in the taxonomy; the cloning and characterization of key genes involved in the critical biological processes of bamboo, such as rhizome bud development, rapid growth, flowering and stress-tolerance; the accomplishment of bamboo genome and transcriptome sequencing projects; and the establishment of genetic transformation systems. The progresses in bamboo molecular biology research provide new insights into further biological studies in Bamboo.

Abstract:Hainan Island is a tropical island and the second largest island along the coast of China. The history, present situation of bryological researches in Hainan Island were reviewed. Based on published records, there are 806 species of bryophyte in Hainan Island, belonging to 227 genera of 87 families, of which 366 species in 71 genera of 33 families are liverworts, 436 species in 152 genera of 51 families are mosses, and four species in four genera of three families are hornworts. The Hainan Island bryoflora is dominant by Tropical Asian type, and has high phytogeographical similarity to Hong Kong and Taiwan. Regional studies on bryological investigations focused on Jianfengling, Bawangling and Diaoluoshan Nature Reserves. Epiphyllous liverworts is one of the commonest coenotypes of the tropical rainforests in Hainan Island, with 123 species belonging to 23 genera of seven families. There are 15 species of bryophytes from Hainan Island listed in the national red list of China. In the future, it should be considered to carry out the extensive and sustained diversity investigation, develop the researches in bryological ecology, chemistry and molecular biology, and promote the utilization and conservation of bryophytes.

Abstract:Lodoicea maldivica (Gmel.) Pers. is the species with the largest seed in the world.