西瓜绵腐病菌生物学特性研究

Biological characteristics of Pythium aphanidermatum causing watermelon fruit rot

本文针对辽宁省西瓜生产上近年趋重发生的绵腐病,通过病原菌形态特征观察、柯赫氏法则证病试验、rD-NA-ITS序列测定及分析,确定其致病菌为瓜果腐霉(Pythium aphanidermatum);并对该病原菌的主要生物学特性进行了研究。试验结果表明:菌丝在黄瓜煎汁培养基、蔗糖培养基、硫酸铵、甘氨酸培养基中生长最适;其生长最适温度35℃,最适pH为6～8;光照对菌丝生长影响较小;菌丝致死温度为51℃,10min。产生孢子囊以菠菜煎汁培养基为最适,在麦芽糖、硝酸钾培养基中孢子囊产生量最大;产生孢子囊的最适温度为25℃、最适pH为8;光照培养产生孢子囊数量最多。

Watermelon fruit rot occurs much more seriously in some areas of Liaoning Province, one of the main watermelon production areas in China. Based on morphological characteristics, Koch rule and the sequences of ri- bosomal DNA-ITS, the pathogen was identified as Pythiurn aphanidermatum. The biological characteristics of P. aphanidermatum were studied. The results showed that the mycelia could grow best on the cucumber media; the mycelia could grow better on the sucrose, ammonium sulfate and glycine media. The optimum temperature for mycclial growth was 35 ℃ ; the optimum pH was 6--8. mycclial lethal temperature was 51 ℃, 10 rain. Spinach duced most sporangia on maltose and potassium nitrate. ℃. Thc optimum pH was 8, and the mycelia produced The effect of light on mycelial growth was not evident and media was best for sporangia production; the mycelia pro- The optimum temperature for sporangia production was 25 more sporangia under light condition.