高温胁迫对景天植物膜脂过氧化及保护酶活性的影响

研究高温胁迫对景天植物的膜脂过氧化程度及保护酶活性的影响。以5种景天植物为试材，进行45℃/30℃（白13 h/昼11 h）高温胁迫，高温胁迫前及胁迫后每5天取叶片测定相关生理指标，分析膜脂过氧化程度及保护酶活性的变化。随着高温胁迫程度加重，5种景天植物的O2.-产生速率和MDA含量持续上升，耐热性强的景天植物O2.-产生速率上升慢、MDA含量积累少；胁迫过程中，5种景天植物的SOD、POD、CAT活性均高于胁迫前，说明高温胁迫诱导3种酶活性增强，3种酶活性在整个胁迫过程中呈现先升后降的趋势，耐热性强的景天植物SOD、POD、CAT活性增幅高。高温胁迫下通过增强SOD、POD、CAT活性以减轻膜脂过氧化程度是景天植物适应高温胁迫的重要生理机制。

Effects of High Temperature Stress on Lipid Peroxidation and Protective Enzyme Activity in Sedum Plants

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.