Biology and Fertility of Soils

, Volume 39, Issue 2, pp 112–116

A microcosm study on the influence of pH and the host-plant on the soil persistence of two alfalfa-nodulating rhizobia with different saprophytic and symbiotic characteristics

Authors

  • M. F. Del Papa
    • Instituto de Bioquímica y Biología Molecular, Facultad de Ciencias ExactasUniversidad Nacional de La Plata
  • M. Pistorio
    • Instituto de Bioquímica y Biología Molecular, Facultad de Ciencias ExactasUniversidad Nacional de La Plata
  • L. J. Balagué
    • Instituto de Bioquímica y Biología Molecular, Facultad de Ciencias ExactasUniversidad Nacional de La Plata
  • W. O. Draghi
    • Instituto de Bioquímica y Biología Molecular, Facultad de Ciencias ExactasUniversidad Nacional de La Plata
  • C. Wegener
    • Lehrstuhl für Genetik, Fakultät für BiologieUniversität Bielefeld
  • A. Perticari
    • IMYZA–Instituto Nacional de Tecnología Agropecuaria
  • K. Niehaus
    • Lehrstuhl für Genetik, Fakultät für BiologieUniversität Bielefeld
    • Instituto de Bioquímica y Biología Molecular, Facultad de Ciencias ExactasUniversidad Nacional de La Plata
Original Paper

DOI: 10.1007/s00374-003-0690-6

Cite this article as:
Del Papa, M.F., Pistorio, M., Balagué, L.J. et al. Biol Fertil Soils (2003) 39: 112. doi:10.1007/s00374-003-0690-6

Abstract

The acid tolerance of Sinorhizobium meliloti in culture media and in soils is considered a useful criteria to select for strains with improved survival in agricultural acidic soils. Using a glass tube system with gamma-irradiated soil at different pH values, we analysed the survival of two different alfalfa-nodulating rhizobia: S. meliloti (pHlimit for growth 5.6–6.0) and the acid-tolerant Rhizobium sp. LPU83, closely related to the strain Rhizobium sp. Or191 (pHlimit for growth below 5.0). Although the acid-tolerant rhizobia showed a slightly better survival during the first months in acid soil (pH=5.6), none of the strains could be detected 2 months after inoculation (bacterial counts were below 103 colony-forming units (cfu)/30 g of soil). The inclusion of two alfalfa plants/glass tube with soil, however, supported the persistence of both types of rhizobia at pH 5.6 for over 2 months with counts higher than 9×106 cfu/30 g of soil. Remarkably, in the presence of alfalfa the cell densities reached by S. meliloti were higher than those reached by strain LPU83, which started to decline 1 week after inoculation. Although more acid-sensitive in the culture medium than the Or191-like rhizobia, in the presence of the host plant the S. meliloti strains showed to be better adapted to the free-living condition, irrespective of the pH of the soil.

Keywords

Glass tube systemSoil acidityAlfalfa

Copyright information

© Springer-Verlag 2003