福建荔枝酸腐菌的生物学特性研究

Biological Characteristics of Geotrichum candidum from Lychee in Fujian

对福建省分离的荔枝酸腐病菌的形态学特征、生长速度、产孢、分生孢子萌发及侵染的影响因子进行研究。结果表明:福建荔枝酸腐病的病原菌为白地霉(Geotrichum candidum);该菌最适生长温度为24～28℃,pH值为8～9,光照时间为12～20h,最适生长与产孢培养基为PDA,分生孢子致死温度为65℃,10min;该菌分生孢子的萌发率与pH值、培养基、光照时间、温度及营养成分等有关,其中该菌在24～32℃,光照时间为16～20h,培养15d时所产生的分生孢子萌发率最高;该菌不同培养时间所产生的分生孢子及不同温度条件对其侵染荔枝的能力也不同,培养10d所产生的分生孢子侵染力最强,侵染最适温度为28～32℃。该菌除了寄生荔枝外,人工接种还能侵染胡萝卜、番茄、水蜜桃、龙眼、葡萄、茄子和黄瓜。试验结果为进一步了解该病的发生危害提供理论依据。

An isolate collected from lychee fruit infected with sour rot in Fujian was detected in terms of mycelial growth, sporulation and conidial germination for pathogenic identification, and the factors influencing pathogenic infection were also observed. This isolate was identified as Geotrichum candidum. For the mycelial growth of G. candidum, the optimum growth conditions were that temperature ranged from 24 to 28 ℃, pH 8-9 and illumination 12-20 h. The best medium for the growth and sporulation of the fungus was PDA. The lethal temperature for conidia was 65 ℃ . Moreover, the effects of pH, medium, illumination duration, temperature and nutrients on the conidial germination of the fungus were studied. The results showed that the conidia cultured for 15d at 24-32 ℃ with 16-20 h of illumination had the highest germination rate. And, the conidia having different ages or at different temperatures had different capacities infecting lychee fruit. When cultured for 10 d, the conidia had the strongest infectivity, and the optimum temperature for their infection ranged from 28 to 32 ℃. Apart from lychee, this pathogen could also infect carrot, tomato, peach, longan, grape, eggplant and cucumber under artificial inoculation. This experiment provides a theoretical basis for further understanding of the occurrence and damage of the litchi sour rot disease.