玉米感染禾谷镰刀菌后PAL、POD活性和同工酶谱的变化

为了明确苯丙氨酸解氨酶活和过氧化物酶活与玉米对镰刀菌茎腐病的抗性关系，探讨玉米对镰刀菌茎腐病的抗病机制及其在玉米抗病性鉴定中的利用，用禾谷镰刀菌孢子悬浮液对抗病品种陕单931和感病品种西农11号在抽雄初期进行接种，并于接种后测定茎秆髓部组织内的PAL,POD活性变化以及POD同工酶谱的变化。结果表明，玉米植株受镰刀菌侵染后，抗病品种的PAL酶活上升快，活性强，且形成两个活性高峰，高活性时间持续长；感病品种PAL酶活上升慢，活性相对较弱，且只形成一个峰，高活性持续时间短。抗病品种POD酶活峰值高，感病品种峰值低；抗病品种高酶活持续的时间长，感病品种高酶活持续的短。POD同工酶谱研究表明，抗、感品种POD同工酶带都有增多。抗病品种增5条，感病品种新增2条。PAL活性变化、POD活性变化及同工酶谱酶活变化与其对茎腐病的抗性有密切的关系，可作为抗病育种的生理生化指标。

Changes of activities of PAL and POD and bands of POD isozyme of Susceptible and resistant corn infected with Fusarium graminearum

In order to understand the relationship between Phenylalanine ammonia-lyase (PAL) activity,peroxidase (POD) activity and resistance of corn to stalk rot,and to explore the resistant mechanism of corn to stalk rot,which might be used to assess the resistance to stalk rot in corn breeding,changes of PAL activity,changes of POD activity and isoperoxidase in the pith tissue of corn stalk of resistant variety Shaandan 931 and susceptible variety Xinong 11 inoculated with F.graminearum were mainly studied.After inoculation,PAL activity of Shaandan 931 was strong and increased rapidly and showed two peaks,while that of Xinong 11 was comparely weak and increased slow and showed only one peak.Both Shaandan 931 and Xinong 11 showed one POD activity peak after inoculation.But the peak value of POD activity of Shaandan 931 was higher than that of Xinong 11 and the duration of high POD activity of SHaandan 931 lasted longer than that of Xinong 11.Five new isoperoxidase band emerged in Shaandan 931 after inoculation while two new isoperoxidase band emerged in Xinong 11.It was postulated that PAL activity or POD activity and the increased number of isoperoxidase after the infection of F.graminearum could be used as indicators of resistance of corn to stalk rot.