外源脱落酸对连作障碍下栝楼抗氧化酶系的影响

Effect of Exogenous Abscisic Acid on Anti-oxidative Enzymes of Replanted Trichosanthes kirilowii Maxim

在金华地区选取连作3年的栝楼(Trichosanthes kirilowii Maxim.)为试验材料,通过浇灌不同浓度(0,2.5,5,7.5,10 mg·L^(-1))脱落酸(ABA),在正常连作情况下测量其叶片的抗氧化酶系活性,探究外源脱落酸缓解栝楼连作障碍的作用机制,为缓解栝楼连作障碍提供理论依据。结果表明:在正常连作情况下,栝楼幼苗经过外源ABA连续处理7 d,处理结束后再过7 d对叶片进行采样测定酶活性,发现超氧化物岐化酶(SOD)、过氧化物酶(POD)、过氧化物酶(CAT)、多酚氧化酶(PPO)、苯丙氨酸解氨酶(PAL)、抗坏血酸过氧化物酶(APX)活性总体随处理的外源ABA浓度的升高而呈现先增强后减弱的趋势。除了PPO酶活性的峰值出现在外源ABA浓度为7.5 mg·L-1外,其余酶的酶活性峰值均出现在5mg·L^(-1)。在过高的外源ABA浓度下,SOD、POD、CAT的酶活性出现低于对照组的现象,推测过高浓度的外源ABA可能不利于连作植物生长。由隶属函数分析得出,5 mg·L^(-1)的外源ABA可以有效缓解栝楼的连作障碍。

To figured out the mechanism of mitigating the injure of continuously-cropping obstacle with abscisic acid Trichosanthes kirilowii which had continuously cultivated for three years under normal circumstance was chosen as experimental materials to explore the effect of abscisic acid(ABA) which irrigating with different concentrations(0, 2.5, 5, 7.5, 10 mg·L^(-1)) on activities of antioxidant enzymes in leaves. The results showed that the activities of antioxidant enzymes of Trichosanthes kirilowii seedlings which had treated with exogenous ABA for seven days and measured activity of superoxide dismutase(SOD), peroxidase(POD), peroxidase(CAT), polyphenol oxidase(PPO), phenylalanine ammonia lyase(PAL) and ascorbate peroxidase(APX) of the leaves sample after another seven days showed a downward trend after a rise trend under normal circumstances. In addition to PPO activity which peak concentration of exogenous ABA is 7.5 mg·L^(-1), the remaining enzyme activities peaks occurred at 5 mg·L^(-1). When the concentration of exogenous ABA is too high, it appeared the phenomenon that the SOD, POD and CAT activities are lower than the activities of control group and other disadvantageous circumstances. The membership function analysis concluded that when the concentration of exogenous ABA is 5 mg·L^(-1), the ABA can effectively alleviate the injury of continuously-cropping obstacles of Trichosanthes kirilowii.