渗透胁迫对蒙古冰草幼苗保护酶系统的影响

用PEG-6000模拟干旱胁迫处理蒙古冰草（Agropyron mongolicum Keng）幼苗，研究了渗透胁迫对蒙古冰草幼苗某些酶活性的影响。结果表明：在轻度干旱胁迫下，蒙古冰草幼苗可以通过提高酶活性来维持活性氧产生与清除之间的平衡，以减少干旱胁迫介导的氧化胁迫，使MDA含量、膜透性降低。在中度或重度干旱胁迫下，酶活性可能遭受破坏，即使酶活性得到一定程度的提高，也不能维持活性氧产生与清除之间的平衡，使植物产生氧化伤害。

Effect of Osmotic Stress on Activities of Protective Enzymes System in Agropyron mongolicum Seedling

After submerging Agropyron mongolicum Keng seedlings roots with PEG-6000 solution, we studied the effect of water stress due to PEG-6000 on activity of protective enzymes (SOD, POD, CAT) in Agropyron. The results showed that, in slight water stress, the Agropyron seedlings could keep the balance of production and scavenging of active oxygen by heightening activities of the enzymes, and reduce the oxidic stress resulting from osmotic stress, and reduce the content of MDA and permeability of cell membrane; but in middle or severe stress, activities of the enzymes decreased, even though some of activities of the enzymes increased, it could not keep the balance of production and scavenging of active oxygen. The content of MDA and permeability of cell membrane strikingly increased and the seedlings were damaged heavily.