氟乐灵诱发棉苗对棉枯萎病的诱导抗性及其机制

 从氟乐灵作播前处理的土壤中长出的棉苗,在出苗1周后移植到无氟乐灵土壤中人工接种棉花枯萎病菌(Fusariumoxysporum f.sp.vasinfectum),30天后棉苗枯萎病株发病率及病菌分离率明显低于对照,说明氟乐灵播前土壤处理可激发棉苗对棉枯萎病的诱导抗性。并证明:氟乐灵处理促进了棉苗组织内木质素的合成与积累;提高了苯丙氨酸解氨酶和过氧化物酶的活性;过氧化物酶同工酶出现了若干新的谱带。

TRIFLURALIN-INDUCED RESISTANCE OF COTTON TO FUSARIUM WILT DISEASE AND ITS MECHANISMS

Pretreating cotton seedlings with herbicide (Trifluralin)markedly increased their resistance to cotton wilt caused by Fusarium oxysporum f. sp. vasinfectum. It was found that the wilt incidence and the pathogen isolation frequency from the seedlings of both resistant and susceptible cultivars were significantly reduced by pre-emergence treatment with trifluralin. It is convinced that the chemical has induced the host resistance to the wilt.The lignin contents of the seedlings treated with trifluralin at pre-emer-gence were higher than that of the untreated seedlings. It was shown that trifluralin treatment promoted lignin accumulation in the host tissues and its effects lasted at least 21 days after emergence.The activities of both phenylalanine ammonia lyase (PAL)and peroxidase in the seedling tissues treated with trifluralin at pre-emergence were siguificantly higher than that of the untreated ones. The composition of peroxi-dase isozymes was also changed in treated seedlings with some new isozymes bands occurred.