两株Frankia菌的研究

THE STUDY OF TWO ISOLATES OF FRANKIA

从大花胡颓子(Elacagnus macrantha)和矮杨梅(Myrica nana)根瘤中分离得到两株Frankia菌,Em2和Mn2,它们都具有典型Frankia菌的形态学特征。Em2菌株在营养培养基上也能分化出泡囊,但这种泡囊的固氮力极低,而在诱导培养基上形成的泡囊固氮力却较高,说明泡囊的分化不完全受环境中氨态氮的控制,而Frankia菌的固氮活性却明显受到氨态氮的影响.在离体条件下,Frankia菌能够自己同化它所固定的氮。

Two isolates of Frankia, Em2 and Mn2 were isolated from Elaeagnus macrantha and Myrica nana. Both of them hava the typical morphological characteristics of Frankia. Em2 even could differentiate the device of vesicle when grown on nutritious medium, and this kind of vesicle has a very lower nitrogen fixing activity. When grown on inducing medium, the vesicles formed by Em2 have a relative high (nitrogen fixing.) activity. It was found that the differentiation of vesicle was not controlled completely by the ammoniacal nitrogen in the environment, but the activity of nitrogen fixing enzyme was obviously influenced by ammoniacal nitrogen. In vitro growth, Frankia could assimilate ammonia by themselve.