枯萎病菌侵染后棉苗体内超氧物歧化酶和过氧化氢酶活性的变化及与抗病性的关系

Changes in activities of superoxide dismutase and catalase in cotton seedling after infection with Fusarium oxysporum f.sp. vasinfectum and their relations to the resistance

分析了枯萎病菌侵染后棉苗叶 片和根茎部组织中超氧物歧化酶（ Ｓ Ｏ Ｄ）和过氧化氢酶 （ Ｃ Ａ Ｔ）活性的变化动态， 结果表明：抗病品种 和感病品种棉苗 中 Ｓ Ｏ Ｄ 和 Ｃ Ａ Ｔ 酶活性无显著 差异；氟乐灵处 理可诱发棉苗对枯萎病的诱导抗性，且氟乐灵处理的棉苗组织中 Ｓ Ｏ Ｄ 和 Ｃ Ａ Ｔ 酶活性无显著变化；枯萎病菌侵染后棉苗叶 片和根茎部组织 中 Ｓ Ｏ Ｄ 和 Ｃ Ａ Ｔ 酶活 性明显提 高，但抗病品 种棉苗组 织中 Ｓ Ｏ Ｄ 和 Ｃ Ａ Ｔ酶活性在前期 增加不显著，后期增 加较慢，而感病品 种棉苗中两种酶活 性在前期就明 显升高，增加 速度快；氟乐灵处理的棉苗，其组织中两种酶活性始终低于未处理棉苗 接种后的水平⒚棉花组织中的 Ｓ Ｏ Ｄ 酶主要是 Ｃｕ， Ｚｎ Ｓ Ｏ Ｄ，受侵后 Ｓ Ｏ Ｄ 酶活性的升高主要来自于 Ｃｕ ， Ｚｎ  Ｓ Ｏ Ｄ⒚因此， Ｓ Ｏ Ｄ 和 Ｃ Ａ Ｔ

Changes in activities of superoxide dismutase (SOD) and catalase (CAT) in leaves and stems/roots of cotton seedlings after infection with Fusarium oxysporum f.sp. vasinfectum were studied. No significant difference in activities of SOD and CAT in cotton seedlings was observed between the resistant cultivar and susceptible cultivar. Presowing treatment of soils with trifluralin, which had been demonstrated to induce the resistance of cotton seedlings to Fusarium wilt, did not affect the activities of SOD and CAT. After inoculation with the pathogen, the activities of SOD and CAT in the seedlings of susceptible cultivar showed earlier and more significant increase than those in the resistant one. When inoculated with the pathogen, the trifluralin treated seedlings of both resistant and susceptible cultivar showed lower activities of SOD and CAT than the untreated ones of respective cultivar. Moreover, the increased activity of SOD in cotton seedlings after infection were mainly due to the increases in the activity of Cu, Zn SOD. It is unlikely that the increased activities of SOD and CAT play a role in the resistance and trifluralin induced resistance of cotton seedlings to Fusarium wilt instead of being a biochemical indicator of susceptible response.