Two sweet potato varieties with different responses to
water stress condition,Chaoshu 1(drought tolerant) and Okinawa 100(drought
sensitive),were used as experimental materials to study the metabolism of
active oxygen in leaves of sweet potato under
water stress.The results showed that the activities of superoxide dismutase (SOD),catalase (CAT),and ascorbate peroxidase (ASP) decreased in both two varieties,the peroxidase (POD) increased at first,then decreased in Chaoshu 1,but decreased from beginning in Okinawa 100.The contents of ascorbic acid (ASA) increased,the contents of glutathione (GSH) increased after slightly decreased.The accumulation of hydrogen peroxide (H 2O 2) and superoxide anion radical (O - 2) increased the permeability and the lipid peroxidation of the plasma membrane and prompted the accumulation of malonadehyde (MDA).The variation degrees were different in two varieties.The relationship between metabolism of active oxygen and drought tolerance of varieties was discussed.