制约稻粒黑粉病菌冬孢子萌发的关键因素

Key factors influencing chlamydospore germination of rice kernel smut

在相同条件下,从稻田直接收集的病粒中的稻粒黑粉病菌厚垣孢子不能萌发,而取之于仓库中的孢子能萌发。为探明其制约因素,对该病菌进行了光照和浸水时间试验。研究结果表明:稻粒黑粉病菌冬孢子形成后,必须经光照射后,方可进入休眠期;度过5～6个月休眠期的冬孢子,必须浸水48h以上才开始复苏;复苏后的冬孢子必须在光照条件下才能萌发。未完成后熟作用的冬孢子和完成后熟但尚未复苏的冬孢子即使在光照条件下也不能萌发。即稻粒黑粉病菌冬孢子必须经历后熟、休眠、复苏三个阶段后,在适宜的光照与温湿条件下,方可萌发。光照对其冬孢子具有双重作用,促使后熟进入休眠和刺激萌发。

It was found that chlamydospores in diseased grains collected from rice field did not germinate, while those from rice storage room did well under the same germination conditions. To understand the germination key factor ( s) , light illumination to diseased grains and water culture for chlamydospores were conducted for this experiment. The results showed that chlamydospores of rice kernel smut enter into post-ripening, the rest period after light illuminated; light illumination was critical factor for passing post-ripening; the spores spending 5-6 months of rest period, revived in water culture for more than 48 h. These revived spores germinated only under light illumination. Therefore, chlamydospores of rice kernel smut germinated well under optimum conditions, such as light illumination, after passing three stages of post-ripening, rest period and reviviscence. It should be emphasized that light illumination had double effects in stimulating post-ripening and germination of chlamydospores of rice kernel smut.