铁元素诱导烟草抗PVY^N的调控作用研究

The Resistant to PVY^N and Defensive Enzymes of Tobacco Induced by Iron

采用病情指数调查、DAS-ELISA和生理生化指标测定的方法,研究了铁元素对烟草抗马铃薯Y病毒脉坏死株系(PVYN)的室内效果及对植株抗病性的诱导作用。结果表明:当烟草叶面喷施铁元素浓度为33.60 mg·L-1时,烟株显症时间要迟于对照,使病毒含量降低至7.31mg·mL-1,仅为对照的45%。单独喷施铁元素和喷施铁元素后再接种PVYN处理,均能提高烟株体内过氧化物酶(POD)、过氧化氢酶(CAT)和多酚氧化酶(PPO)活性,并且在短时间内使活性氧的生成速率提高1.6倍,叶绿素a的含量提高1.4倍,表明铁元素能诱导烟株防御反应的应答,但对苯丙氨酸解氨酶(PAL)影响不大。此外,铁元素处理后再接种PVYN的烟株体内PPO活性一直呈缓慢上升趋势,在12d内略高于接种对照烟株,而12d后为显症时期,接种对照烟株体内的PPO活性迅速上升为6463.54U.mg-1pro·h-1,是铁元素处理后接种烟株的1.5倍,表明PPO与叶脉褐变密切相关,而铁元素处理可以抑制PPO活性的快速提高,从而减轻褐变症状。因此,喷施铁元素后可以诱导烟草植株产生抗病性,增强烟草对PVYN侵染的抵抗力。

The resistance induced by spraying iron against potato virus Y-vein necrosis strain （PVY^N） on tobacco was studied. The results showed that the symptom appeared later and the content of virus （7.31mg.mL^-1） were much lower than that of control when treated with iron 33.6mg.L^-1. Except phenylalanine ammonia-lyase （PAL）, the tobacco either inculcated or no inoculated the activities of peroxidase （POD）, eatalase （CAT） and content of Chlorophyll a increased than that of control when treated with iron at concentration of 33.6mg.L^-1. The production rate of activated oxygen raised 1.6 times in a short time after treatment, those indicated that the induce resistance of tobacco was induced. The activities of polyphenold oxidase （PPO） in tobacco leaves which treated with iron before inoculation, were higher than those of the control in 12days. But it was down to 4296.68U.mg^-1pro.h^-1, much lower than that of the control after the 12^th day, which showed that the degree of vein browning was related to the PPO activity decreasing. In conclusion spraying iron could induce tobacco plant resistance to PVY^N.