稻曲病菌厚垣孢子侵染时期和侵染途径的研究

用田间自然发病病粒上新形成的稻曲病菌厚垣孢子,喷雾或注射接种不同生育期的稻穗获得成功。水稻孕穗末期至破口期是稻曲病菌厚垣孢子侵染的主要时期。在孕穗末期喷雾接种2次萌发孢子的发病率高达50.8%。解剖736个病粒内部都含有花药,镜检119条花药和35个柱头发现,病粒内大多数花粉粒的内容物已基本充实,柱头大多处于分枝状突起阶段。解剖刚发病的病粒柱头上有多根菌丝,并向花药等处扩展。萌发的厚垣孢子可以侵染处于乳头状突起期的柱头,并形成菌丝及产生小孢子。稻曲病菌厚垣孢子主要在水稻破口前1—4天至破口时从水稻的柱头侵入引起发病。

STUDIES ON THE INFECTION PERIOD AND THE INFECTION GATE OF THE CHLAMYDOSPORES OF USTILAGINODEA VIRENE(COOKE) TAK.ON RICE

The tests were successful using germinating or nongerminatingchlamydospores of false smut pathogen(Ustilaginodea virens)to inoculaterice of different growing stages by spraying or injecting spores.Theend at boot stage and the rupturing stage of rice are the main periodsfor the infection of chlamydospores of Ustilaginodea virens.The diseaserate of 50.8% by spraying germinating spores on rice was appeared atthe end of the boot stage.Anthers were observed in all 736 diseasedgalls.It was found that the contents of the majority of polleas werealmost perfect and the stigmata were at the branched heading stage in119 anthers and 35 stigmata.Many hyphae were found in the examinedstigmata of late diseased kernals and they intented to spread to anthers.The germinating chlamydospores could infect the stigmata of papillaryheading stage.They could also produce hyphae and microspores.Thechlamydospores might infect the stigmata of rice mainly during the pe-riod of one to four days before rupturing till rupturing time.