稻曲病早期症状鉴别及水稻雄性不育系的抗病性鉴定

Observation of Invading Process of Rice False Smut and Its Resistant Identification of Rice Male Sterile Lines

[目的]了解在自然发病情况下稻曲病菌[Ustilaginoidea virens(cooke)Tak]的侵入时期和侵入部位,为进一步研究该病的侵入机制提供参考。[方法]用光学显微镜观察水稻孕穗期的幼穗花器,研究稻曲病菌的侵染过程,并对水稻雄性不育系的抗病性进行了鉴定。[结果]该菌是在抽穗前8 d左右从上下颖壳间的缝隙中侵入的。该菌随机到达各种花器上,但到达花药的几率最大。然后菌丝上下扩展,当到达花丝的上部或/和柱头上时就会生长得更快,因为那里营养更多。该菌不侵入子房,是因为子房的细胞小而排列紧密,病菌无法穿透。该菌是授粉前侵入花器的,说明水稻雄性不育系也可发病,可以进行抗病性鉴定。[结论]试验结果为水稻生产上有效防治该病提供了理论依据。

[ Objective ] Invading period and site of Ustilaginoidea virens （cooke） Tak under natural infection conditions were understood to provide reference for further study the invasion mechanism. [ Method] In booting stage the floret organs of rice young panicle were observed by optical microscope to demonstrate the invading process of Ustilaginoidea virens （cooke）Tak. The resistance of rice male sterile lines was identified, [ Result] The fungus invaded the lloret through the crack between up and lower lemmas before about 8 days of heading. The hyphae reached the orguns of floret by chance and got great chance to reach the anthers. Then the hyphae extended up and down and grew much faster when they reached stamen filaments and/or stigmas because at there they could get much nutrition transported to the anthers by stamen filaments and from ovary. The fungus could not invade ovary because that cells of ovary are tiny and tightly jointed so that the hyphae could not penetrate ovary. The fungus invaded floret before pollination and that the fangus could invade rice male sterile lines, It was suggested and demonstrated that the resistance of male sterile lines to false smut could be evaluated. [ Conclusion] The results provide theoretical basis for the control of rice false smut in production.