不同玉米品种对大斑病的抗性与相关防御酶活性的关系研究

以吉林省玉米早熟、中早熟区种植的4个玉米品种及其亲本为材料，对不同玉米品种对大斑病的抗性与苯丙氨酸解氨酶（PAL）、过氧化物酶（POD）和多酚氧化酶（PPO）等3种防御酶活性的关系进行研究。结果表明，3种防御酶PAL、POD和PPO与玉米对大斑病的抗性关系非常密切，玉米植株受大斑病菌侵染后，防御酶活性比对照明显增高。防御酶的作用受品种遗传背景的影响，不同品种中不同防御酶对其大斑病抗性的贡献有差异。受大斑病菌侵染后，抗病性强的品种，PAL和PPO或PAL和POD酶活性发生协同增强，且从抽丝期到灌浆期酶活性协同增强的防御酶不发生酶活性衰减或衰减微弱；感病的品种，从抽丝期到灌浆期存在2种或3种防御酶活性同时衰减现象。

Defense Enzyme Activities and the Resistance to Northern Leaf Blight of Different Hybrids in Maize

Four maize hybrids and their parental lines widely planted in early-maturity and mid-early maturity zones as materials, relations of the resistance to northern leaf blight in diverse maize hybrids with defense enzyme activities of phenylalnine ammonialyase(PAL), peroxidase(POD) and polyphenoloxidase(PPO) were investigated. The results showed that the activities of defense enzymes PAL, POD and PPO were highly related to maize resistance to northern leaf blight. In addition, the defense enzyme activity in maize leaves after infected with northern leaf blight pathogens was obviously increased in comparison with control. The function of these defense enzymes may be affected by genetic backgrounds of maize hybrids, and the contribution of each defense enzyme in an individual hybrid to the resistance to maize northern leaf blight was different. After infected by maize northern leaf blight, for the resistant hybrids, activities of two defense enzymes both PAL and PPO or both PAL and POD were simultaneously enhanced, and no attenuation of enzyme activity of these defense enzymes at filling stage occurred in comparison with those at silking stage. In contrast, for the susceptible hybrids, activities of two or three defense enzymes were simultaneously attenuated.