干旱胁迫下牛心朴子幼苗相对含水量、质膜透性及保护酶活性变化

牛心朴子(Cynanchum komarovii)幼苗用不同浓度PEG-6000(聚乙二醇)模拟干旱处理,测定处理12d和复水24h中根、叶的RWC、质膜相对透性、MDA含量及几种保护酶(SOD、CAT、POD)活性变化情况,结果表明：高浓度胁迫后期,RWC明显下降,MDA含量增大,致使膜脂过氧化引起膜损伤;低、中浓度胁迫下,RWC下降程度低,细胞膜脂过氧化及膜透性影响小,且可能对膜脂过氧化起到一定的防御作用。复水后,低、中度胁迫下,各项指标能迅速恢复到CK水平,而高浓度胁迫下,除叶质膜透性、MDA含量、SOD活性不能恢复外,根、叶的其余指标均能达到CK水平。保护酶系统的作用,在一段时间内,可能是通过它们之间的相互协调而保持一个稳定的平衡态进行的。

Effects of drought stress on system of defense enzymes and RWC and membrane electrolyte in Cynanchum komarovii seedlings

Cynanchum komarovii seedlings were treated with different concentrations of PEG-6000 solutions.RWC,cell membrane electrolyte leakge,content of MDA and activities of several defense enzymes (such as SOD,CAT,POD) of roots and leaves were determined 12 days after treatment and 24 hours after rewatering.The results showed that under the high concentrations PEG,RWC decreased significantly,while the content of MDA increased.Lipid peroxidation and injury of cell membrane were caused in the later stayes of the treatment.On the contrary,Lipid peroxidation and cell membrane electrolyte leakge were influenced less,and RWC had a decrease slightly.Under low concentrations,after rewatering,every indexes recovered to the levels of CK quickly under low stress,but under high stress,except cell membrane leakaye of leaves,content of MDA and activity of SOD,the other indexes recovered to the levels of CK.This results suggested that the system of the defense enzymes might play a key role by balancing all of the responding enzymes under drought condition in plants.