UV-B辐射对不同生态型垂穗披碱草幼苗生长和抗氧化酶系统的影响

UV-B辐射是影响植物生长的外界限制因子之一。本文研究了UV-B辐射对2个生态型垂穗披碱草（Elymus nutans）（商用型正道，ZD；西藏野生型申扎，XZ）幼苗的生长和抗氧化系统的影响。结果表明：UV-B辐射处理后，二者的生物量和叶绿素含量受到不同程度地抑制，ZD地下生物量和根茎比受UV-B辐射抑制作用显著；处理后二者的丙二醛含量显著提高，且XZ的丙二醛含量显著低于ZD；UV-B还显著增加了垂穗披碱草幼苗的可溶性蛋白含量，ZD的脂氧合酶活性也有显著提高，但XZ并无显著变化；另外，幼苗的超氧化物歧化酶和过氧化物酶活性受UV-B辐射影响均不显著，但XZ的超氧化物歧化酶活性显著高于ZD，而过氧化物酶活性显著低于ZD；二者的过氧化氢酶和谷胱甘肽还原酶活性受UV-B辐射影响显著，但生态型间无显著差异。综上，XZ受UV-B辐射影响小于ZD，对UV-B辐射有较高抗性，这可能与其稳定的脂氧合酶活性和较高的超氧化物歧化酶活性等有关。

Effects of UV-B Radiation on the Growth and Antioxidative Enzymes System of Two Eco-types Elymus nutans Seedlings

UV-B radiation is one of the limiting factors affecting plant growth. The effects of UV-B radiation on the growth and antioxidative enzymes system of two ecological types of Elymus nutans (Commercial type from Beijing zhengdao,ZD;Tibetan wild-type from Xainza,XZ) seedlings were studied using sand culture method. The results showed that the biomass and chlorophyll content of two eco-types of E. nutans were inhibited to varying degrees after UV-B radiation treatment,and the growth of ZD's below-ground biomass and root-shoot index was significantly inhibited. UV-B radiation treatment significantly increased the malondialdehyde content of E. nutans,and the malondialdehyde content of XZ was significantly lower than ZD. And,UV-B radiation significantly increased the soluble protein content of E. nutans, and lipoxygenase activity of ZD increased significantly,but there was no significant difference between the UV-B radiation treatment and the control in XZ. The superoxide dismutase and peroxidase activities of two eco-types E. nutans didn't not change significantly after UV-B radiation treatment. The activity of superoxide dismutase in XZ was significantly higher than that in ZD,while the activity of peroxidase was significantly lower than that in ZD. However,the activities of catalase and glutathione reductase were significantly affected by UV-B radiation,but there was no significant difference between the two eco-types. It is reasonably to infer that XZ is less affected by UV-B radiation than ZD and has higher resistance to UV-B radiation,which may be related to its stable lipoxygenase activity and higher superoxide dismutase activity.