干旱胁迫对玉米幼苗脂质过氧化作用及保护酶活性的影响

采用人工控水的方法,考察了土壤含水量9%、12%、15%、18%、21%及24%6个梯度下玉米种子的萌发率,玉米幼苗膜脂过氧化指标H2O2、MDA及叶绿素含量,幼苗自由基清除相关酶SOD、CAT与POD活性等生理生化指标的变化。结果表明,随着土壤含水量的下降,玉米萌发率及叶绿素含量呈现下降的趋势,玉米幼苗H2O2与MDA含量呈现上升的趋势,且干旱胁迫越严重趋势越明显;幼苗自由基清除相关酶活性的变化各不相同,SOD活性在干旱胁迫初期呈上升趋势,后期呈下降趋势,POD与CAT活性在干旱胁迫初期变化不大,后期则呈下降趋势。因此,干旱胁迫能加剧玉米幼苗膜脂过氧化从而引起膜的损伤,且膜脂过氧化的程度随干旱胁迫的加大而加大,幼苗自由基清除相关酶活性在胁迫初期会上升以抵抗干旱胁迫,后期则下降,且不同的酶在抗干旱胁迫中的作用不同。植物在干旱胁迫下保护酶系统的作用,可能是通过它们之间相互协调且保持一个稳定的平衡态而进行的。

Effect of Drought Stress on Lipid Peroxidation and Activity of Cell Defense Enzyme in Maize Seedling

Maize were grown in plastic pots in a greenhouse under different water content in soil,including 9%,12%,15%,18%,21% and 24% water content in soil.Germination rate and content of H_2O_2,MDA and chlorophyll were measured.Also,enzymatic antioxidants such as SOD,POD,CAT,etc,which could clean AOS and exist in plant cells,were studied.The results showed that germination rate and chlorophyll content were decreased and H_2O_2 and MDA content were increased with the increasing of water content of soil.SOD activities raised and POD and CAT activities had no significantly chang in light drought-stress.But with more drought-stress,they decreased.This results suggested that the system of the defense enzymes play a key role through balancing all of the responding enzymes under drought condition in plants.