新疆玉米普通锈病(Puccinia sorghi Schw)侵染生活史及初侵染源研究

目的]研究玉米普通锈病在新疆自然的生境条件下,个体发育中各个孢子世代的生物表现型及其初侵染源形式.方法]采集玉米普通锈病孢子,分析夏孢子和冬孢子存活能力,并将病原菌接种于玉米上观察发病情况.结果]菌初侵染时期和整个夏季所生成夏孢子堆的生物特性,只是为病原在寄生生活周期内营扩大再侵染的繁殖用.夏孢子的萌发和侵染的适宜温度为10.8～29℃,最适温度为14.9～22.4℃,温度在10℃ 以下萌发终止.玉米收割后,夏孢子在寄主基质上可残生时间约在55 d以内,至11月26日检验其活性时,发现许多夏孢子体内的颗粒体已消耗殆尽,形成透明的空腔,有的则失去光泽,呈现淡灰褐色,丧失了发芽能力,鉴此看出该病夏孢子抗逆性很差,不能逾越新疆漫长严酷的寒冬.研究还发现,临秋时节,玉米病体上出现一种深锈褐色的休眠夏孢子堆的菌态,此菌态有强劲抗逆性的特异功能,在持续2个多月零下20～24℃ 的寒冬期后,仍具有正常的萌发力和对寄主侵染的致病毒性.结论]在新疆的冬季,玉米普通锈病是以休眠夏孢子堆作为越冬世代,而且是玉米在生产中感染锈病唯一的初次感染源.该病冬孢子世代在新疆的侵染生活史上并无实质性的病理学意义.

Research on the Infection Cycle of Corn Rust Disease(Puccinia sorghi Schw.)in Xinjiang

【Objective and Method】In 2007,there was a corn rust disease outbreak in Qitai County,Xinjiang.This outbreak had an impact on 100,000 acres of corn plantation and also infected the adjacent Mulei County,in which there were approximately 10,000 acres of corn plantation infected.Thus far,the cause of this corn rust disease outbreak is unclear.The paper studies the biological phenotype of various ontogenetic spore phases for the rust disease under the specific ecological environmental condition in Xinjiang.Moreover,this paper also investigates the primary infection source of the corn rust diseae.【Result】Based on this research,it is shown that starting from the primary infection in the summer,the formation of the specific biological characters of the urediniospores is only to provide the reproductive resources for the expansion and re-infection during the parasitic life-period.The suitable temperature range for the urediniospore germination and infection is between 10.8 and 29℃,and the best range is between 14.9 and 22.4℃.When the temperature range is below 10℃,the germination will terminate.Statistically,after the corn is harvested from the field,urediniospore can live on the host substratum for 55 days.On November 26,2007,when the ability for germination was examined,it was found that the particle substance in the urediniospores had become void,or less shining,coloring in gray/brown and showing no germination activity.【Conclusion】It can be found that the corn rust urediniospore does not have a good