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在含有儿茶素的培养液中棉枯萎病菌(Fusarium oxysporum f. sp. vasinfectum)的多聚半乳糖醛酸酶(PG)和果胶裂解酶(PL)活性明显降低。儿茶素可明显抑制初步纯化的PG和PL活性以及它们对棉苗组织的浸软作用。对棉苗组织中儿茶素含量的测定结果表明:抗病品种棉苗组织中儿茶素含量较高;氟乐灵处理可诱发棉苗产生对枯萎病的诱导抗性,同时也提高棉苗组织中的儿茶素的含量;枯萎病菌侵染后棉苗组织中儿茶素含量明显升高,以抗病品种棉苗和氟乐灵诱发处理棉苗组织中儿茶素含量的增加更为明显。棉苗组织提取液中的酚类物质可抑制PG和PL的活性,且证明这种抑制作用主要是由儿茶素引起。提取液对PG和PL活性的抑制作用与棉苗组织中儿茶素的含量呈直接的正相关关系。因此,作者认为棉苗组织中的儿茶素可能通过对病菌PG和PL等胞壁降解酶的抑制而与棉花对枯萎病的抗病性及氟乐灵诱发的诱导抗性有关。
The activities of polygalacturonase (PG) and pectin lyase (PL) in Fusarium oxysporum f. Sp. Vasinfectum were significantly decreased in the medium containing catechin. Catechin significantly inhibited the initial purification of PG and PL activities and their maceration of cotton seedlings. The results showed that the content of catechins in the cotton seedlings tissues was higher than that in the cotton seedlings. The treatment with trifluralin could induce the cotton seedlings to induce the resistance to Fusarium wilt, The content of catechins in the tissue; Fusarium oxysporum infection in cotton seedlings tissue catechin content was significantly increased, the resistant varieties of cotton seedlings and trifluralin-induced cotton seedling tissue catechins increased more obvious. Phenols in extracts of cotton seedling tissues inhibited the activity of PG and PL, and it was demonstrated that this inhibitory effect was mainly caused by catechin. The inhibitory effect of extracts on PG and PL activities was directly and positively correlated with the content of catechins in the tissue of cotton seedlings. Therefore, the authors believe that the catechins in cotton seedling tissues may be related to the resistance of cotton to Fusarium wilt and the induction of trifluralin-induced resistance by the inhibition of cell wall degrading enzymes such as PG and PL.