棉花感染枯萎病后糖含量及蔗糖酶活性的变化及其与抗病性的关系

Changes in contents of sugars and invertase activity in cotton seedings after infection by Fusarium oxysporum f. sp. vasinfectum:

２μｇ＿ａ．ｉ／ｇ土壤的氟乐灵作播前土壤处理可诱发棉苗对枯萎病的诱导抗性，处理组棉苗枯萎病的株发病率和病情指数明显降低。对棉苗叶片和根茎部组织中总糖、可溶性糖及还原糖含量以及蔗糖酶活性的测定结果表明，抗病品种棉苗中总糖、可溶性糖和还原糖含量以及蔗糖酶活性均低于感病品种棉苗中的含量和活性。接种枯萎病菌后，两个品种棉苗叶片及根茎部组织中糖含量和酶活性有明显的提高，但抗病品种和感病品种棉苗之间糖含量及酶活性的变化无显著差异。氟乐灵诱发处理的棉苗中糖含量和酶活性均高于对照，但枯萎病菌侵染后氟乐灵诱发处理和未处理棉苗中糖含量的变化也无明显差异。因此，受侵后糖含量和蔗糖酶活性的提高与棉苗对枯萎病的抗病性及氟乐灵诱发产生的诱导抗性无直接关系。

Presowing treatment with triflualin at 2μg a. i. g -1 soil resulted in induced-resistance of cotton seedings to Fusarium oxysporum f. sp. vasinfectum (Fov), with reduced disease incidence and disease severity index. Contents of total sugar, soluble sugar and reduced sugar and activity of invertase in cotton seedlings of resistant cultivar were lower than that of susceptible seedlings. Sugar contents and invertase activity were increased after infection by Fov, but increases of sugar contents and invertase activity in Fov-infected seedlings of resistant and susceptible cultivars had no significant difference. Pretreatment with trifluralin increased the sugar contents and invertase activity in cotton seedlings of two tested cultivars. After infection with Fov, no significant difference was observed in increases of sugar contents and invertase activity in trifluralin-treated and untreated seedlings. Thus, the increased sugar contents and invertase activity in cotton seedlings after infection with Fov were unlikely to play a role in the resistance and trifluralin-induced resistance of cotton seedlings to Fusarium wilt.