西瓜叶枯病病原菌生物学特性研究

Biological Characteristics of the Pathogenic Fungus Causing Leaf Spot Disease of Watermelon

西瓜叶枯病(Alternaria cucumerin)是一种真菌性病害,其致病菌为瓜链格孢菌(Alternaria cucumerin),对该病菌进行了生物学特性研究。试验结果表明:菌丝在PDA与西瓜肉榨汁的培养基上生长较好,菌落直径为8.0cm;菌丝生长最适温度为25℃,菌落直径为7.1cm;适宜生长的碳源为葡萄糖,氮源为硝酸钠,pH值为7,菌落直径分别为7.2,8.7,8.0cm,菌丝致死温度为52℃、10min,菌丝在光照、黑暗、光暗交替下均能生长,其中在光照条件下生长最好。适于病菌孢子萌发的温度为25℃,pH值为7,2%硝酸钠培养液条件下萌发率最高,萌发率为90.2%、95.6%和96.4%。

The leaf spot disease of watermelon is a fungal disease. The biological characteristics of Ahernaria cucumerina was studied. The results showed that the myeelium could grow better on PDA medium and medium of watermelon juice, colony diameter was 8.0cm. 25℃ was the optimum temperature with colony diameter of 7.lcm. For mycelial growth, the suitable carbon source was glucose, the suitable nitrogen source was sodium nitrate, and the suitable pH was 7, with colony diameter of 7.2 cm, 8.7 cm and g.0cm in the three conditions, respectively. The lethal temperature of mycelium was 52℃, 10min. Myeelium could grow in brightness, darkness, and alternating light-dark, best in brightness. For spore germination of pathogen, suitable conditions were 25℃ and pH 7, and the rate of germination was the highest with 2% sodium nitrate, with spore germination rate of 90.2%, 95.6% and 96.4%.