我国首见韭葱疫霉的鉴定

作者分离到国内首见的韭葱疫霉菌Phytophthora porri Foister。观察了菌落形态,对此菌一系列形态与生理生化性状进行了研究。在马铃薯葡萄糖琼脂培养基上,病菌形成光滑、致密、边缘整齐的白色菌落;在胡萝卜琼脂培养基上或水中,病菌皆能形成大量的孢子囊,孢子囊柠檬形或近圆形;单个菌株不能产生有性器官,与P.parasitica A_1直接配对,形成大量的藏卵器、雄器和卵孢子;最高生长温度为37±0.5℃;能够利用硝态氮,但不能水解淀粉;当培养基中孔雀石绿的浓度为10~(-6)时病菌开始生长,伤口接种对马铃薯块茎具有致病性。

IDENTIFICATION OF FIRST REPORTED PHYTOPHTHORA PORRI FOISTER IN CHINA

The authors isolated a Phytophthora from onion. On CA media or in water the fungus produced a lot of sporangia, with ovoid or limon form, length/breadth ratio: 1. 24. A single colony can not produce sex organs. It was able to utilize nitrate-nitrogen as the sole nitrogen source, but not able to utilize soluble starch as the sole carbon source. It grew on PDA which contain 10~(-6) malachite green and produced visible brown colaration on PDA which contain casein hydrolysate-tyrosine. By artificial inoculation, it was pathogenic to wounded potato tuber. According to the keys of Waterhouse (1963), Newhook (1978) and Ho (1981), the fungus was identified as P. porri Foister, discovered in China for the first time.