Effect of Complex Alkali-Saline Stress on Activity of Protective Enzyme in Three Varieties of Tobacco Seedlings

Three common tobacco varieties in Jilin province were stressed with five different gradients of complex alkali-saline during seedling growth stages,then malmldehyde(MDA),proline(Pro) content and change of superoxide dismutase(SOD),catalase(CAT) and peroxidase(POD) activity were detected.The results showed: with the stress prolonging,Pro content increased in early phase and afterwards decreased,MDA content increased actually,SOD and CAT activity gradually declined,POD activity in early phase increased and afterwards declined.In the same stress condition,alkali-saline tolerance of N.rustica was relatively higher and that of flue-cured.tobacco lower.