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Growth and Survival of Cowpea Rhizobia in Acid, Aluminum‐Rich Soils
Author(s) -
Hartel Peter G.,
Alexander Martin
Publication year - 1983
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1983.03615995004700030021x
Subject(s) - rhizobia , soil water , inoculation , rhizobium , soil ph , strain (injury) , biology , rhizobiaceae , chemistry , horticulture , botany , symbiosis , bacteria , ecology , genetics , anatomy
A study was undertaken to determine whether Al‐sensitive cowpea Rhizobium survives in acid, Al‐rich soils. The lower pH limit for growth of 20 strains in a defined liquid medium varied from pH 4.2 to less than pH 3.6. The mean lower limit for growth was pH 3.9. Several of the strains clumped in this medium at pH 4.5. Of 11 strains that were tested for tolerance to high levels of Al in a defined liquid medium at pH 4.5, nine tolerated 75 µ M Al, and the other two were sensitive to levels above 15 µ M . Three strains, one Al‐tolerant, one Al‐sensitive, and one Al‐tolerant or Al‐sensitive depending on the presence of vitamins in the medium, were selected for studies in Al‐rich sterile and nonsterile soils. These rhizobia did not survive in soils of less than pH 4.7 sterilized by 60 Co irradiation. When inoculated into sterile soil at pH 4.7, the consistently sensitive strain initially failed to proliferate and then grew slowly, but populations of the other two rhizobia increased rapidly. No consistent relationship was found between the Al tolerance of these three rhizobia and their growth and survival in four acid, Al‐rich soils. The data suggest that Al is of minor importance to growth and survival of cowpea Rhizobium strains in acid soils.