Symbiotic effectiveness and ecological characterization of indigenous Rhizobium loti populations in Uruguay

Pesquisa Agropecuária Brasileira

Amalia Baraibar¹  Llillian Frioni²  Maria Elena Guedes¹  Hans Ljunggren¹ 

[1] ,Facultad de Agronomia Dep. de Ciências Biológicas Montevideo

关键词: Lotus corniculatus;    Lotus pedunculatus;    rhizobial pH tolerance;    Lotus corniculatus;    Lotus pedunculatus;    tolerância do rizóbio ao pH;   

DOI  :  10.1590/S0100-204X1999000600012

来源: SciELO

【 摘 要 】

The objectives of this work were to describe the distribution, density and seasonal variation of the indigenous populations of Rhizobium loti in different Uruguayan soils and to determine the symbiotic effectiveness and stress tolerance factors of different isolates, both with the aim of obtaining selected strains to re-introduce as inoculants in Lotus pastures. R. loti was present in ten soils studied and their densities varied from year to year and within each soil. All the isolates nodulated Lotus corniculatus effectively. The nodules in Lotus pedunculatus and Lotus subbiflorus were small, red on the surface and ineffective in nitrogen fixation. The study of 50 isolates from the ten soils showed high variability in their symbiotic efficiency and tolerance to pH. The indigenous population was acid tolerant in culture medium (pH 4.5), 83% of them could grow at pH 4.5 in 3 days. This work showed that there was a great diversity between the strains of R. loti isolated from Uruguayan soils and supports the importance of selecting among them the most efficient and resistant strains to be included in the inoculants.

【 授权许可】

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