Abstract:

The work was aimed to investigate effects of high temperature stress on lipid peroxidation and protective enzyme activities in Sedum plants. Five Sedum plants were treated with high temperature of 45℃/30℃ (day 13 h/night 11 h) in plant growth chamber, leaves of five plants were chosen for measurement of all physiological indices before stress and each five days after stress to analyze changes of lipid peroxidation and protective enzyme activities. O2.- production rates and MDA contents of five Sedum plants increased gradually in high temperature stress process, Sedum plants with stronger thermotolerance had characteristics that O2.-production rates increased slowly and MDA contents accumulated slowly; activities of SOD, POD, CAT in stress process were all higher than that before stress, which stated high temperature stress induced higher activities of three enzymes, and three enzyme activities increased at first and then decreased in stress process, three protective enzyme activities of Sedum plants with stronger thermotolerance enhanced obviously compared with other Sedum plants. Reducing lipid peroxidation injury by enhancing protective enzyme activities under high temperature stress was one of significant physiological mechanism to adapt to high temperature stress for Sedum plants.