黄瓜不同抗病品种感染镰刀菌枯萎病菌后几种酶活性的变化

SOME CHANGES OF ENZYME ACTIVITIES FROM SUSCEPTIBLE AND RESISTANT CUCUMBER CULTIVARS AFTER INOCULATION WITH CUCUMBER WILT FUSARIUM

镰刀菌枯萎病的侵染使寄主黄瓜根部的苯丙氨酸解氨酶、过氧化物酶和多酚氧化酶活性增加,抗病、感病各品种的3种酶活性曲线均呈现两个峰值,抗病各品种酶活性峰Ⅰ值比感病品种高。其中,感病品种的3种酶活性峰Ⅱ值大于峰Ⅰ值,而抗病品种酶活性峰Ⅰ值、Ⅱ值则在不同酶里有不同变化。在未感染情况下,抗病品种根部的苯丙氨酸解氨酶、过氧化物酶和多酚氧化酶活性比感病品种高。

The infection of cucumber wilt Fusarium resulted in an increase in phenylalanine ammonia lyase, peroxidase and polyphenoloxidase activities in diseased cucumber roots. Activities of the enzymes showed two peaks in four cucumber cultivars. The increase of the enzyme levels was greater in resistant cucumber roots than that in susceptible ones. In all the three enzyme activity peaks of susceptible cultivar, the second one was higher than the first. However the two peaks of resistant cultivars had different changes varying with different enzymes.These results suggest that early rapid increase of polyphenoloxidase may serve as one of the physiological indices for the selection of cucumber resistant cultivar. The mechnism of disease resistance may be shown by toxic role of phenol oxidases and cell lignification.