Abstract: In order to investigate the dehydration tolerance and physiological responses of Boea clarkeana, detached leaves of four populations of B. clarkeana from Shanxi, Sichuan (hereafter west China), Anhui and Zhejiang (hereafter east China) provinces were subjected to dehydration for 0, 4, 8, 12, 24 and 48 h, respectively, and 48 h after dehydration the same leaves were subjected to rehydration again for 4, 8, 12, 24 and 48 h, respectively. The results showed that the relative water contents of the four populations decreased significantly during the entire dehydration process (P<0.05). The general dehydration tolerance of the four populations was in order of Zhejiang population < Anhui population < Sichuan population < Shanxi population. The relative water contents in the four populations could be recovered to their original states during rehydration. The activities of antioxidant enzymes (SOD, POD, CAT) and contents of osmoregulation substances (MDA, proline, soluble protein, soluble sugar) increased significantly during desiccation and decreased significantly during rehydration (P<0.05). In comparison, the dehydration tolerance of the four populations of B. clarkeana were Shanxi population > Sichuan population > Anhui population > Zhejiang population. The west populations of B. clarkeana had higher dehydration tolerance than the east populations.

Key words: Cd, paddy soil, rice, risk assessment