玉米对镰刀菌茎腐病抗性的生化反应

在抽雄期用禾谷镰刀菌孢子悬浮液接种抗病品种陕单931和感病品种西农11号,于接种后测定茎秆髓部组织内苯丙氨酸解氨酶、过氧化物酶活性变化、木质素和绿原酸的变化。结果表明,玉米植株受镰刀菌侵染后,抗病品种的苯丙氨酸解氨酶酶活上升快,活性强,且形成两个活性高峰,高活性时间持续长;感病品种苯丙氨酸解氨酶酶活上升慢,活性相对较弱,且只形成一个峰,高活性持续时间短。抗病品种过氧化物酶酶活峰值高,感病品种过氧化物酶酶活峰值低,且抗病品种高酶活持续的时间长,感病品种高酶活持续的短。研究还表明,植株原生的木质素对玉米的抗性贡献不大,而诱导的木质素在玉米的抗病性中起着主导作用。同时,无论抗、感品种,其组织诱导提取液对镰刀菌都有一定的抑制作用。

Biochemical reaction of corn resistance to stalk rot caused by Fusarium graminearum

In order to understand the mechanism of corn to stalk rot caused by Fusarium graminearum, changes of PAL activity, POD activity and lignin in the pith tissue of corn stalk of resistant variety Shaandan 931 and susceptible variety Xinong 11 inoculated with Fusarium 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 slowly 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. It was clarified that the lignin produced originally in corn plant had no relation to resistance of corn to stalk rot. It was the induced lignin produced by corn plant after inoculation of F. graminearum that showed contribution to the resistance only. Corn plant could produce some substances that could suppress the growth of F. graminearum when it was infected by F. graminearum.