杨梅共生菌Frankia的分离培养及侵染特性

采用根瘤匀浆和根瘤切片法对福建南部、中部和东北部的杨梅根瘤共生菌进行了分离,并进行菌株培养、初步鉴定及侵染特性检测。结果获得6株共生菌,菌株具有分枝状菌丝、孢囊、泡囊等典型Frankia的特征性结构,经无氮诱导有固氮活性,在BAP液体培养基中生长良好,适宜的碳源为乙酸钠、丙酸钠和丙酮酸钠,适宜的氮源为酪蛋白。5个菌株生理类群为B型,细胞壁化学组分为Ⅲ型,菌株FMr16比较特异,具有串珠状菌丝体,生理类群为A型,细胞壁组分为Ⅱ型。侵染结果表明,6个菌株可侵染杨梅、沙枣、沙棘和四川桤木,但不使木麻黄结瘤,菌丝体接种效果好于根瘤匀浆接种,菌丝体分批接种效果优于单次接种。

Isolation, culture and infection of Frankia strains from the root nodules of Myrica rubra

Six Frankia strains were isolated by crushing the crude nodules of Myrica rubra.The observations by microscopy demonstrated that these strains showed a typical Frankia morphology,with filamentous hyphae,multilocular sporangia borne terminally,laterally,or in an intercalary position on branching hyphae.Nitrogenase activity of strains was monitored in the media on lack of nitrogen and varied greatly among isolates.Five strains were divided into physiological group B and type Ⅲ of cell wall chemical composition.Six strains grew well in BAP medium,the optimum carbon and nitrogen sources were propionate,pyruvate and casein.Results of cross-inoculation demonstrated that six strains had ability to infect M.rubra,Elaeagnus angustifolia,Hippophae rhamnoides and Alnus cremastogym,but not for Casuarina cunninghamiana,C.equisetifolia and C.glauca.It has a significant improvement on the growth,nodulation and total N of leaf by using Frankia inoculum than nodule suspensions.Slight efficiency of the growth and nodulation were obtained from seedlings of M.rubra which inoculated twice with Frankia strains.