西瓜品种抗枯萎病鉴定方法的研究

在培养液中，西瓜枯萎病菌（Fusarium oxysporum f.sp.niveum）产生以镰刀菌酸为主的致萎物质，用50%的枯萎病菌培养滤液浸苗88小时，对不同西瓜品种致萎力的差异情况与品种在病圃中的抗病性表现基本一致。 受枯萎病菌侵染以前，11个西瓜品种的过氧化物酶同工酶差异极小，酶带数及颜色深浅相同。接种枯萎病菌以后，感病品种比抗病品种的过氧化物酶同工酶活性增强，酶带数增加1-2条。同工酶谱中E#-1、E#-7酶带或E#-1酶带的出现与否，是鉴别西瓜品种抗枯萎病的一个生化指标。

STUDIES ON THE APPRAISAL METHODS OF DISEASE RESISTANCE OF WATERMELON VARIETIES TO FUSARIAL WILT DISEASE

In liquid culture, Fusarium oxysporum f. sp. niveum produces toxic substance which mainly is fusarialacid. Test of resistance to wilt was carried out by soaking the 2ndleaf seedlings of eleven watermelon varieties in 50% toxin filtrate for 88 hours. The resistances of eleven watermelon varieties to toxin were correlated with their resistances to watermelon wilt disease.Before inoculation the differences among peroxidase isozymes of 11 watermelon varieties were only a little, and the color and number of the enzyme bands were of the same, After inoculation, the activities of peroxidase isozymes in the 2nd-leaf were inten sified. The enzyme activities of susceptible varieties invariably had one or two more isozyme bands than those of the resistant ones. It is suggested that the appearance of more new isozymes in the susceptible varieties upon inoculation may be used as a biochemical criterion for screening the resistant varieties of watermelon plants from those susceptible to fusarial wilt disease.