杨梅根瘤内生菌的生物学特性

The Biological Characteristics of Actinomycetes Frankia Living in Roots of Myrica rubra

以5株细枝木麻黄、短枝木麻黄、粗枝木麻黄和四川桤木的共生Frankia菌株为对照,研究12株杨梅根瘤内生菌的形态培养特征、生理类群、细胞壁类型、营养源利用、固氮酶、宿主特异性等生物学特性。结果表明:供试菌株具有分枝状菌丝、多腔孢囊、泡囊等典型的Frankia结构,杨梅菌株FMr16、FMr43和木麻黄菌株FCc64、FCe33还具有串珠状生殖菌丝。多数杨梅菌株在有氮培养基中能形成泡囊,固氮活性差异显著。细胞壁类型多为Ⅲ型,菌株FMr16为Ⅱ型。生理类群有A、B和AB3种,同一株杨梅根瘤内有B和AB2种生理类群的菌株共存。菌株能良好利用丙酸钠、丙酮酸钠、乙酸钠、吐温和酪蛋白,部分菌株利用硝态氮、铵态氮和牛肉膏,利用糖类差,不利用蛋白胨和尿素,不使明胶液化,不分解纤维素,不产生硫化氢,不利用苯丙氨酸。杨梅根瘤内生菌可使原宿主结瘤,能感染沙枣和四川桤木,但不侵染木麻黄结瘤,这为菌株的选择应用提供基础。

Systematic studies of the biological characteristic including morphology, culture, physiological group, cell-wall type, nutrient utilization, nitrogenase activity and host specificity, were carried out on 12 strains isolated from the root nodules of actinorhizal plants of Myrica rubra, comparing with five Frankia strains symbiotically associated with Casuaria cunninghamiana, C. equisetifolia, C. glauca and Alnus cremastogyne. As a result, all strains tested showed a typical Frankia morphology, with filamentous hyphae, muhilocular sporangia and vesicles. The specialized reproductive torulose hyphae were found in strains FMrl6 and FMr43 from Myrica same as strains FCc64 and FCe33 from Casuarina. Most of strains from Myria formed vesicles in media which nitrogen exited, and nitrogenase activity varied greatly. Cell wall type of many strains belonged to type Ⅲ , except strain FMrl6 which was type Ⅱ . Strains were found to fall into three physiological groups, one was group A, one was group AB, and the others were group B, both B and AB group strains were found to coexist in a single tree of M. rubra. Strains preferred to utilize sodium propionate, sodium pyruvate, sodium acetate, Tween-80 and NZ amine, but grew poor in presence of saccharide. Some strains utilized potassium nitrate, ammonium sulphate and beef extract, but none of them utilize peptone, urea, glutin and phenylalanine. Strains didn＇ t produce cellulase and H2 S. The result of inoculation showed that strains from M. rubra had an ability to infect the seedlings of M. rubra, A. cremostogyne and Elaeagnus angustifolia, but not infect the seedlings of C. cunninghamiana, C. equisetifolia and C. glauca, so it was a necessary to choose the adaptive strains to use as inoculum.