Abstract:

The effects of high temperature (40℃) on antioxidant system and the accumulation of osmotic adjustment substance of Bromeliaceae seedlings were studied. The results showed that compared to the control, during the early 8 hour of treatment, the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) and the contents of proline (Pro) and heat-shock proteins (HSP) increased significantly. The generation rate of the superoxide free radical (O2-?), hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents, electrolytic leakage, chlorophyll contents changed slightly. No obvious injury was observed in plant growth. The results indicated that the heat tolerance of Bromeliaceae was improved by enhancing the activities of SOD, POD and CAT and the contents of Pro and HSP. With stress time lasting, the activities of SOD, POD and CAT and the contents of Pro, HSP, protein, chlorophyll and carotenoid decreased, but the generation rate of O2-?, H2O2 and MDA contents, electrolytic leakage, free amino acids contents increased significantly. Leaf stomata closed gradually. Young and mature leaves of Bromeliaceae seedlings suffer injury gradually.