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Root exudates in relation to growth and nitrogenase activity of Rhizobium japonicum
Author(s) -
Odunfa S. A.,
Werner D.
Publication year - 1981
Publication title -
zeitschrift für allgemeine mikrobiologie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0044-2208
DOI - 10.1002/jobm.19810210806
Subject(s) - exudate , nitrogenase , nitrogen fixation , root nodule , arabinose , rhizobium , biology , chemistry , botany , biochemistry , bacteria , fermentation , xylose , genetics , gene
Root exudates of cowpea and soybean were collected in aerated water cultures. The ability of these exudates to support nitrogenase activity of R.japonicum was studied on defined media. When a complete nitrogenase‐inducing medium was supplemented with concentrated root exudate, there was an increased nitrogenase activity. When the cowpea root exudate was substituted for glutamine or sodium succinate in the medium, nitrogenase activity was not detected. Growth was good when the root exudate was substituted for sodium succinate but was poor when the exudate replaced glutamine. There was nitrogenase activity in R. japonicum when the cowpea root exudate was substituted for arabinose in the 20E medium. Gas chromatographic analyses of cowpea root exudates revealed that ribose, arabinose, glucose, and sucrose were the main constituents. The significance of this finding in the asymbiotic nitrogen fixation by Rhizobium spp. is discussed.