接种体密度、土壤水分基质势和土壤温度对辣椒疫病死苗率的影响

 在生长箱内控制条件下分析测定了接种体密度、土壤水分基质势和土壤温度对辣椒疫病死苗率的影响。结果表明,在每克干土中接种1个辣椒疫霉菌孢子囊就能造成侵染,引致辣椒死苗,随着接种体密度升高死苗率增大,直至接种体孢子囊密度达到50~80个/g干土时死苗率达到最高。土壤温度和土壤水分状况是决定辣椒疫病死苗率的重要因子,病菌侵染的最适土温是22~28℃,土壤水分接近饱和,即土壤水分基质势(Ψ_m值)为0时最容易侵染发病,土壤过于干燥和过饱和都不利于侵染发病。辣椒疫病死苗率与土壤温度、土壤水分基质势及其互作之间可用数学模式描述。

Effect of Inoculum Density,Soil Water Matric Potential and Soil Temperature on Mortality of Pepper Caused by Phytophthora capsici

In control condition of the growth chamber analyzing the influence of inoculum density,soil water matric potential and soil temperature on mortality of pepper caused by P.capsici,results showed that so long as one sporangium existed in 1 g dry soil,the pepper plant could be infected and dead,the percentage of diseased plant increased with increasing inoculum density up to about 50-80 sporangia in per gram dry soil,and then declined.Soil temperature and soil water status were important factors affecting mortality of pepper blight,and the optimum infection temperature of P.capsici was in range from 22 to 28℃,ψm value approached 0,soil water content approached the saturation,as optimum for the infection of the pathogen sporangia,while soil over-saturation and over-dry were unfavorable for infection of pathogen.The relationship among mortality percentage,soil temperature,ψm value and their interactions were described by mathematical function.