The effects of abscisic acid (ABA) and water stress on senescence and enzym
e activities of oxygen scavenging enzymes of detached rice leaves were comp
ared. Exogenously applied ABA exhibited water stress-like effects by promot
ing senescence, by decreasing the activities of catalase, peroxidase, ascor
bate peroxidase and superoxide dismutase. It seems that the effects of wate
r stress on senescence and enzyme activities are possibly mediated through
increased content of endogenous ABA.