Understanding the drivers of population divergence, speciation and species persistence is of great interest to molecular ecology, especially in the world's biodiversity hotspots. East Asia is one of regions harboring the most diverse temperate and subtropical flora in the world. Although this region has never been directly impacted by extensive and unified ice-sheets, it nonetheless experienced severe environmental change throughout the Late Tertiary and Quaternary with dramatic effects on the evolution and distribution of plants. By using phylogeographic, landscape genetic, and ecological modelling approaches, a steadily increasing number of phylogeographic studies in East Asia have documented the evolutionary web of population demographic, biogeographic, and speciation processes. This symposium will present recent remarkable studies concerning phylogeographic patterns, population demographic/biogeographic histories, speciation processes, as well as drivers of species diversification and persistence that have given rise to one of the world's most diverse floras in East Asia.
Global/overview Carbohydrate Energy Lipid Nucleotide Amino acid Other amino Glycan
Cofactor/vitamin Terpenoid/PK Other secondary metabolite Xenobiotics Chemical structure
2. Genetic Information Processing
3. Environmental Information Processing
4. Cellular Processes
5. Organismal Systems
6. Human Diseases
7. Drug Development
【Objective】The objective of this paper is to study accumulation characteristics and health risk of heavy metals in greenhouse vegetable base of Beijing, to determine the migration rule of heavy metals from soil to vegetable, and to provide reference basis for vegetable quality safety and optimization of vegetable structure in Beijing. 【Method】 148 soil samples and 96 vegetable samples were collected from 9 typical greenhouse vegetable bases in Beijing, the statistical characteristics of As, Cd, Cr, Hg and Pb in soil and vegetable samples and their transfer factors from soil to vegetable system were analyzed. Combined with the EPA (US) recommended health risk assessment model, the health risks of adults and children as a result of vegetable intake were evaluated. 【Result】 The mean concentrations of As, Cd, Cr, Hg and Pb in soils were , , , and mg·kg -1 , respectively. The mean concentrations of As, Cd, Cr, Hg and Pb in vegetables were , , , and mg·kg -1 , respectively. On the whole, the migration ability of heavy metals in greenhouse vegetable bases were decreased in the order of Cd ＞Hg＞Cr＞As＞Pb. Target hazard quotients caused by heavy metals were decreased in the order of Cd＞Pb＞Hg＞As＞Cr. The target hazard quotient of single heavy metal in all vegetable samples was less than 1, which indicated that there was no obvious negative effect of single heavy metal. 【Conclusion】 The accumulation of heavy metals (As, Cd, Cr and Hg) in the soil samples from the greenhouse vegetable bases were found, health risks should be emphas ized.