The effects of exogenous abscisic acid (ABA) on lead tolerance in rice (Oryza sativa L.) seedlings were investigated. Pre-treatment with 0.1 g m 3 ABA for 2 d restricted amount of Pb translocated from roots to shoots, decreased malondialdehyde and H 2 O 2 contents in leaves, and alleviated Pb-induced decrease in plant growth and leaf chlorophyll content. Further, ABA pre-treatment adjusted leaf antioxidative enzyme activities (increased ascorbate peroxidase and catalase activities while decreased superoxide dismutase activity) and so alleviated oxidative stress.

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