不同光强对曼地亚红豆杉扦插苗叶片膜脂过氧化和膜保护酶活性的影响

Effects of Light Intensity on Membrane Lipid Peroxidation and Protective Enzyme Activities in Leaf of Taxus media

以不同光强下的5年生曼地亚红豆杉为研究对象,以不作遮荫的自然光强作为对照,探讨了光强对其苗木叶片膜脂过氧化和膜保护酶活性的影响。结果表明:与对照相比,一层遮荫(70%的透光率)的T1光强处理提高了其苗叶膜保护酶SOD、POD、CAT、APX的活性和抗氧化物质ASA的含量,降低了其O2.-产生速率、H2O2和MDA含量,从而使其苗木膜脂过氧化维持在一定水平。而二层遮荫光强处理的苗木叶片CAT活性较对照增强,但苗叶的SOD活性随其遮荫时间的延长而降低,其POD、APX活性及ASA含量均较对照低,而使其O2.-产生速率、H2O2和MDA含量先低后高。三层遮荫光强处理的苗木叶片保护酶活性及ASA含量均较对照降低,其O2.-产生速率、H2O2和MDA含量上升。由此表明,一层遮荫的光强处理提高了曼地亚红豆杉扦插苗叶片清除活性氧的能力,是曼地亚红豆杉扦插苗在重庆低海拔地区培育的最适光环境。

Taking 5 years old cuttings as materials, the effects of light intensity on membrane lipid peroxidation and protective enzyme activities in leaf of Taxus media were studied. The results show that one-layer shade （70 % of full sunlight） increases the activity of protective enzyme such as SOD, POD, CAT and APX and the content of antioxidative material, but decreases O2·^ - production rate, and the contents of H2O2 and MDA, thus can keep the leaf of the membrane lipid peroxidation the fixed standard. Under two-layer shade, O2·^ - production rate, and the contents of H2O2 and MDA are from low to high, because of SOD activity decreases with the increasing of the time of shade treatment and decreasing of POD, APX activity and ASA content, inspite of the increasing of CAT activity. Under three-layer shade, O2·^ - production rate, and the contents of H2O2 and MDA are increased, because of decreasing of protective enzymes＇ activities. It is concluded that one-layer shade raise the ability of scavenging free radical and that it is the most suitable environment planted in the low elevation area in Chongqing.