PEG模拟干旱胁迫对入侵植物牛膝菊（Galinsoga parviflora）抗氧化物酶系统的影响

利用不同质量分数PEG-6000溶液，对牛膝菊（Galinsoga parviiflora）植株（株高30-40cm）进行干旱胁迫处理，研究了其叶片MDA（丙二醛）和可溶性蛋白含量、SOD（超氧化歧化酶）及POD（过氧化物酶）活性．结果表明，随着干旱胁迫强度增加，MDA含量、sOD活性和POD活性均呈现先上升后下降的趋势．PEG质量分数为20％时，MDA含量、SOD活性和POD活性达到最大值；PEG质量分数为15％时，可溶性蛋白含量达到最大值；PEG质量分数达到25％时，MDA含量、可溶性蛋白含量、SOD活性和POD活性降低．不同PEG质量分数处理，MDA含量、SOD活性、POD活性（除5％PEG外）均高于CK，但差异不显著（P〉0．05），而不同PEG质量分数处理下可溶性蛋白的含量均低于CK，差异也不显著（P〉0．05）；随着干旱胁迫时间的延长，在不同PEG质量分数处理下，牛膝菊叶片MDA含量、SOD活性显著增加，可溶性蛋白含量显著减少，而POD活性具有明显阶段性变化：0～24h时间段，10％～20％PEG处理组POD活性呈递增趋势；24～48h时间段，10％～20％PEG处理组POD活性下降显著；48-72h时间段，10％～20％PEG处理组POD活性变化不明显，25％PEG处理组和CK的POD活性上升显著．

Effect of PEG Simulative Drought Stress on Antioxidant Enzyme System of Galinsoga parvi flora

Set different drought gradients by use of polyethylene glycol 6000 solution and measure Galinsoga parviflora physiological indicators in drought environment, which are MDA（Malondialde hyde）, soluble protein, superoxide dismutase activity and peroxidase activity. Malondialdehyde mass fraction, superoxide dismutase activity and peroxidase activity showed an increasing trend firstly and then decreased; MDA, superoxide dismutase activity and peroxidase activity were all max at 20% PEG. Soluble protein mass fraction was max at 15% PEG. MDA, Soluble protein mass fraction, superoxide dismutase activity and peroxidase activity showed a decreasing trend at 25% PEG. MDA, superoxide dismutase activity and peroxidase activity were all more than CK; differences were not significant. Soluble protein mass fraction was less than CK at PEG different concentrations. And differences were not significant. Firstly MDA and superoxide dismutase activity showed increasing trend at PEG different concentrations; peroxidase activity of 10% -20% PEG showed a increasing trend during 0 - 24 hours. Peroxidase activity of 10% - 20% PEG treatment group decreased significantly during 24-48 hours. Peroxidase activity change of 10% -20% PEG treatment group was not obvious during 48 - 72 hours. Peroxidase activity of 25% PEG treatment group and CK showed an increasing trend during 48-72 hours.