小麦白粉菌有性时期闭囊壳在侵染循环中作用的初步研究

通过对陕西省和河南省小麦白粉病越夏期间场院麦秸垛中闭囊壳发育、存活情况及场院附近自生麦苗发病情况的调查,结果发现闭囊壳保湿培养7~8 d后,子囊孢子形成达到高峰;自生麦苗发病率与闭囊壳存活率之间存在极显著的正相关性,且闭囊壳存活率与海拔高度之间存在显著的负相关性,采自海拔500~900 m的闭囊壳有较高的存活率,海拔超过1 000 m的存活率较低或为零。此结果说明小麦白粉菌有性时期闭囊壳可能是通过侵染自生麦苗在侵染循环中起作用。

The contribution of chasmothesia of Blumeria graminis f. sp. tritici to its infection cycle

The vigor of chasmothesia of Blumeria graminis f. sp. tritici sampled from the stacks of wheat straw in Henan and Shaanxi provinces were observed under light microscope and the occurrence of powdery mildew on volunteer seedlings near the stacks were surveyed during the summer period. The results indicate that the formation of ascospores reached the peak 7-8 days after chasmothesia incubated under moistened conditions. The vigor of chasmothesia was positively correlated to incidence of powdery mildew on volunteer seedlings, but was negatively related to altitude. Chasmothesia, sampled from 500 to 900 m above the sea, had higher livability; while vigor of those from above 1 000 m was low or even reached zero. These results indicate that the contribution of chasmothesia of B. graminis f. sp. tritici from stacks of wheat straws is to infect the volunteer seedlings and then disperses to autumn seedlings in disease cycle.