Abstract: This paper studied the plant composition and diversity in a uranium tailings reservoir area in Central South China, and measured the environmental radiation. A total of 79 plant species were recorded, belonging to 32 families and 67 genera. The importance value of the plants at the habitats with different radiation intensity differed greatly. At the habitats of low or medium radiation intensity, the importance value of the plants was relatively disperse, and the three layers of tree-bush-grass all had many dominant species; while at the habitats with high radiation intensity, a few of dominant species appeared. Based on the plant importance value, community similarity coefficient, and cluster analysis, the plant community in the study area could be divided into four types, i.e., Cinnamomum camphora＋Broussonetia papyrifer—Loropetalum chinense＋Vitex negundo—Macleaya cordata＋Phytolacca acinosa community at the habitats of low radiation intensity, Melia azedarach＋B. papyrifer—V. negundo＋Mallotus apelta—M. cordata＋Miscanthus floxidulus community at the habitats of medium radiation intensity, and Mallotus apelta—Phragm ites australis＋Imperata cylindrica community and Rhus chinensis—Setaria viriisd＋Imperata cylindrica＋Paspalum scrobiculatum community at the habitats of high radiation intensity. Shannon diversity index (H) ranged from 0.463 to 1.734, with the order of low radiation intensity habitat ＞medium radiation intensity habitat ＞high radiation intensity habitat. The Margalef richness index (D_MA) ranged from 33.962 to 9.024, and the Pielou evenness index (Jsw) ranged from 0.463-0.986. The eco-environmental problems of the uranium tailings reservoir area were discussed.

Key words: Secalonic acid F, Aspergillus japonicus, Allelopathy, Zea mays