土壤环境对大豆疫霉Phytophthora sojae卵孢子萌动的影响

Effects of soil environment on activation of oospores of Phytophthora sojae

为明确土壤环境对大豆疫霉Phytophthora sojae卵孢子萌动的影响,将增强型绿色荧光蛋白标记的大豆疫霉卵孢子以2 500个卵孢子/g干土的比例接种于无菌黑土中,荧光显微镜下计数卵孢子的萌动率以明确其最适宜的土壤温度和含水量;在此基础上,从5种类型土壤和5种轮作体系土壤中筛选适宜卵孢子萌动的土壤环境。结果表明,25℃土壤温度和30%土壤含水量最适合大豆疫霉卵孢子萌动,萌动率为95.78%;黑土和盐碱土分别是最适合和最不适合卵孢子萌动的土壤类型,萌动率分别为94.94%和14.67%;卵孢子萌动率与土壤有机质含量、p H值和Ca2+含量间无明显相关性。大豆连作田和玉米连作田土壤适合卵孢子萌动,萌动率为96.33%和95.00%,小麦连作田土壤不适合卵孢子萌动,萌动率仅为39.33%。

In the present study,the oospores marked by the enhanced green fluorescent protein (EGFP) were inoculated at a certain proportion to the Mollisols through a sterile Eppendorf tube to determine the most suitable soil temperature and water content by calculating the activation rate of oospores under the fluorescent microscope.The same method was used to measure the oospore activation rate in five types of soils and five types of crop rotation soils under the most suitable soil temperature and soil water content to determine the most suitable soil environment.The results showed that the soil temperature of 25 ℃ and the soil water content of 30％ were the most suitable for oospore activation,with an activation rate of 95.78％.Mollisols and Halosols were the most suitable and unsuitable soil types,respectively,for the activation of oospores,with an activation rate of 94.94％ and 14.67％,respectively.There was no correlation between the activation rate of oospores and pH value,organic matter and Ca2+ content of the soil.Also,the soil from soybean mono-cropping field and corn mono-cropping field were more suitable for the activation of oospores than that from wheat mono-cropping field,with an activation rate of 96.33％,95.00％ and 39.33％,respectively.