XVI International Botanical Congess

Cytokinins exhibit a wide range of physiological and biochemical effects to plant. It has also been reported that cytokinins could induce stress resistance of plant.Chilled rice (Oryza sativa L.) seedlings were treated with 6-benzyladenine (6-BA),the increases of superoxide dismutase (SOD) and catalase (CAT) activities and decreases of malondialdehyde (MDA) and cell electrolyte leakage were observed. The SOD located in chloroplasts was more sensitive to low temperature than that in mitochondria or in cytosol. The electron microscope observation indicated that the membrane structure of chloroplast and mitochondria of chilled rice seedling was badly damaged. But when the seedlings were pretreated with 6-BA, the structures of chloroplast and mitochondria were in better condition. When 6-BA was combined with antioxidants, the coordination for cell membrane system protection was observation.