黄瓜黑星病菌二菌系的菌丝生长及分生孢子萌发生理的研究

黄瓜黑星菌二菌系（即甘肃菌系和沈阳菌系）分生孢子和菌丝生长的适温为２０～２２℃；在１：５的瓜叶汁液中，１２ｈ后甘肃菌系和沈阳菌系的分生孢子萌发率分别为７３％和６９％。而牛粪浸出液对二菌系分生孢子的萌发有一定的抑制作用，萌发率均低于对照。二菌系对碳源和氮源的利用存在明显的差异，如甘肃菌系在葡萄糖、果糖、蔗糖、木糖和乳糖等培养基上生长量为５．７ｍｍ／ｄ以上，而沈阳菌系仅约３１ｍｍ／ｄ；氮源中以硝酸铵、胱氨酸对甘肃菌系生长的刺激作用明显，生长量分别为６４ｍｍ／ｄ和５８ｍｍ／ｄ，而沈阳菌系仅为３５ｍｍ／ｄ和３４ｍｍ／ｄ。但精氨酸则对二菌系的生长有抑制作用，日生长量低于对照５０％以上。

Mycelia Growth and Conidia Germination of Two Strains of Cladosporium cucumernum in Vitro

The optimum temperature for mycelia growth and conidia germination of two strains (Gansu strain and Shenyang strain) of Cladosporium cucumerinum range from 20 to 22℃. Conidia germination rates of Gansu strain and Shenyang strain can reach to 73 % and 69 % respectively in juice of cucumber leaves (1 : 5) after 12 hr. However the two strains are inhibited in infusion liquid of cow dung, the rates of conidia germination show lower than CK. There is significant difference in the two strains on utilization of carbon and nitrogen source, eg., growing speed of Gansu strain is over 5 7 mm/d on culture medium of glucose, fructose, sugar, xylose and lactose, but Shenyang strain is only about 3 1mm/d on above said culture medium. NH 4 NO 3 and cystine can stimulate remarkable the growth of Gansu strain, growing speed of the colony are 6 4 mm/d and 5.8 mm/d respectively. but Shenyang strain are only 3 5 mm/d and 3 4 mm/d respectively. The growth of two strains are inhibited on arginine culture medium. Daily growth speed is lower above 50 % than CK.