三裂叶豚草霜霉病的病原鉴定及生物学特性研究

Research on Pathogen Identification and Biological Characteristics of Plasmopara Occurring on Ambrosia Trifida L

对霜霉菌的生物学特性进行了系统研究。结果表明：该菌的孢子囊萌发的适宜温度为15-20℃,最适温度18℃;孢子囊萌发需较高的湿度,湿度低于95%时孢子囊不萌发;可溶性淀粉对孢子囊的萌发有强烈的促进作用,用可溶性淀粉溶液处理孢子囊3 h后,其萌发率由原来的37.7%提高到90.9%;低温处理孢子囊,会降低霜霉菌孢子囊的萌发力,处理时间越长,孢子囊的萌发力越低。恒温条件下,在10-20℃范围内随着温度的升高,霜霉菌侵染能力增强;保湿时间低于2 h,霜霉菌不能侵染豚草,说明湿度条件是影响三裂叶豚草发病与否的重要因素。

In the paper,the systemic research on the biological characteristics of downy mildew is conducted. The results show that the preference temperature range for its sporangium germination is from 15 to 20℃ with the optimal temperature of 18℃. Sporangium germination needs higher humidity because humidity is below 95% sporangium fails to germinate. Soluble starch has a strong role in promoting the sporangium germination; after being treated with soluble solution for 3h,the germination rate of sporangium increases from 37. 7% to 90. 9%. The treatment of sporangium under the condition of low temperature reduces the sporangia germination ability.the longer the processing time is,the lower the germination ability is. Under the condition of constant temperature,within the scope of 10 ℃ - 20 ℃,with the increase of temperature,downy mildew infection ability enhances. When the moisturizing time is less than 2h,downy mildew can＇t infect Ambrosia trifida,which shows humidity condition is the important factor affecting the morbidity of Ambrosia trifida.