Abstract: Taking seedlings of Dodonaea viscosa, Leucaena leucocephala and Tephrosia candida from Jin Sha River as materials, the effects of drought stress on their lipid peroxidation and activity of defense enzymes under natural drought stress were studied in contrast to effects under watering. The results show that the cytomembrane permeability, MDA content, SOD and POD activity are all more or less changed under drought stress although the extent and process of variation is different. As for Leucaena leucocephala seedlings, MDA is not the main product of lipid peroxidation and Tephrosia candida seedlings do not only rely on SOD and POD action to reduce active oxygen content. Through comprehensive analysis on water holding capacity of leaf, cytomembrane permeability, MDA content and SOD, POD activity, Dodonaea viscosa seedlings show the highest drought resistance, then Leucaena leucocephala, Tephrosia candida the last.

Key words: Dodonaea viscosa, Leucaena leucocephala, Tephrosia candida, drought stress, lipid peroxidation, defense enzymes