稻瘟病菌粗毒素对水稻光系统Ⅱ(PSⅡ)的影响

Effect of Magnaporthe oryzae crude toxin on photosystemⅡof hybrid rice

【目的】明确稻瘟病菌对杂交水稻光系统的毒害机制。【方法】采用ZA10、ZA14、ZA18、ZC11 4个稻瘟病菌生理小种粗毒液浇灌水稻植株,探讨4个稻瘟病菌生理小种毒素对不同生育时期冈优725叶片叶绿素荧光参数(最大光能转化效率(Fv/Fm)、潜在光化学活性(Fv/Fo)、实际光能转化效率(ΦPSⅡ)、非循环光合电子流速率(ETR)、光化学淬灭系数(qP)、非光化学淬灭系数(qN)、初始荧光(Fo)、叶片表观量子效率(α))的影响。【结果】稻瘟病菌毒素处理后,冈优725叶片的光系统受到破坏,Fv/Fm、Fv/Fo、ΦPSⅡ、ETR、qP、qN、α显著降低,而Fo显著升高。不同稻瘟病菌生理小种毒素的毒力差异显著,且随着浓度的增高毒素对水稻光系统的影响作用增强,其中ZA10毒力最强。【结论】稻瘟病菌毒素能引起水稻叶片类囊体膜受损和反应中心破坏,光合电子传递效率降低,光保护能力削弱;稻瘟病菌生理小种与水稻生育时期对叶绿素荧光参数存在极显著的互作效应,在孕穗期对毒素最敏感,在拔节期最耐受。

【Objective】This study aimed to clear the toxicity mechanism of Magnaportheoryzaeon light system of hybrid rice.【Method】Crude toxins from four races of Magnaporthe oryzae,including ZA10,ZA14,ZA18,and ZC11,were irrigated to rice plants to study the influence of Magnaporthe oryzae toxin on the chlorophyll fluorescence parameters（Fv/Fm,Fv/Fo,ΦPSⅡ,ETR,qP,qN,Fo,andα）at different growth stages of Gangyou 725.【Result】After being treated by crude toxin,the photosystem in leaves of Gangyou 725 was destroyed,with significantly decreased Fv/Fm,Fv/Fo,ΦPSⅡ,ETR,qP,qN andαvalues,and significantly increased Fo value in blade of Gangyou 725.There were significant differences among four physiological races of Magnaporthe oryzae.With the increase of concentration of toxin,the effects on rice increased.The toxin of ZA10 toxin was the strongest.【Conclusion】The toxin of Magnaporthe oryzae damaged the thylakoid membrane and photosystem Ⅱreaction center in leaves of rice.It resulted in lower photosynthetic electron transport rate and decreased the ability of protection from light.There were significant interaction effects between growth stages of rice and physiological races on chlorophyll fluorescence parameters.Booting stage was the most sensitive stage,while jointing stage had the strongest tolerance.