Open AccessNitrogen fixation in pure culture by rhizobia isolated from stem nodules of tropical Aeschynomene species
Author(s) -
Alazard Didier
Publication year - 1990
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1990.tb04145.x
Subject(s) - nitrogenase , nitrogen fixation , rhizobia , bradyrhizobium , biology , botany , diazotroph , root nodule , agar plate , bacteria , genetics
Asymbiotic nitrogenase activity was investigated in rhizobia strains isolated from stem and root nodules of severa Aeschynomene species. All isolated from stem‐nodulating species were able to develop nitrogenase activity ex planta in the presence or in the absence of combined nitrogen, whereas root isolates from Aeschynomene species related to the cowpea group of plants showed little or no activity. Nitrogenase activity in soft‐agar and in liquid cultures displayed by strains ORS310 and ORS322, isolated from stem nodules of A. indica and A. afraspera respectively, was of the same order of magnitude as that found for Azorhizobium caulinodans ORS571 and ten times higher than for Bradyrhizobium strain CB756. Furthermore, like A. caulinodans ORS571, strains ORS310 and ORS322 were able to use atmospheric nitrogen as sole nitrogen source for growth.