Tolerance to water stress in transgenic sweet potato expressing both SOD and APX

摘要

Two genotypes,Cu/Zn SOD and APX gene transferred sweet potato (TS) and non-transgenic sweet potato Upomoea batatas L. Yulmi) (NT) ,were used to study the drought tolerance in three different water stresses of 0,-0.44 MPa, - 0.78 MPa. Results showed that activities of Cu/Zn superox-ide dismutase (SOD) and ascorbate peroxidase (APX) increased under-0.44 MPa and decreased under - 0.78 MPa,net photosynthesis (Pn),stomatal conductance (Gs) and tissue water content decreased, intercellular CO-2 concentration (Ci) increased, then decreased under water stress,but under the same stress conditions,these indexes in the TS were always higher than in NT. The accumulation of hydrogen peroxide (H-2O-2) and superoxide anion radical (O~-2) increased the lipid peroxidation of the plasma membrane,prompted the accumulation of malondialdehyde (MDA),and the accumulation in the TS was always lower than the NT at the same PEG concentration. All these suggested that the transgenic sweet potato have stronger abilities to clean up active oxygen than the non-transgenic one, and can keep a higher tissue water content and Pn rate under water stress,expressing stronger drought resistant capability.