Open AccessEffects of phenoxy acid herbicides and glyphosate on nitrogenase activity (acetylene reduction) in root‐associated Azospirillum, Enterobacter and Klebsiella
Author(s) -
Haahtela Kielo,
Kilpi Sisko,
Kari Kirsti
Publication year - 1988
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.1574-6968.1988.tb02655.x
Subject(s) - nitrogenase , pseudomonas , enterobacter , acetic acid , chemistry , pantoea agglomerans , microbial inoculant , bacteria , microbiology and biotechnology , nitrogen fixation , biology , biochemistry , escherichia coli , gene , genetics
Abstract Nitrogenase activity (C 2 H 2 reduction) in root‐associated Azospirillum lipoferum, Klebsiella pneumoniae, Enterobacter agglomerans and Pseudomonas sp. isolated from roots of Finnish grasses was assayed in the presence of glyphosate, the phenoxy acid herbicides 2‐methyl‐4‐chlorophenoxy acetic acid (MCPA), 2,4‐dichlorophenoxy acetic acid (2,4‐D), (±)‐2‐(2‐methyl‐4‐chlorophenoxy)propionic acid (mecoprop) and (±)‐2‐(2,4‐dichlorophenoxy)propionic acid (dichlorprop), and the commercial products Roundup, Nurmikko‐Hedonal, Mepro, and Dipro. In the presence of the phenoxy acid herbicides the nitrogenase activity of K. pneumoniae was significantly inhibited, but that of E. agglomerans was stimulated. With the exception of Mepro and mecoprop no phenoxy acid herbicides inhibited the nitrogenase activity of A. lipoferum and none that of Pseudomonas sp. Nurmikko‐Hedonal considerably stimulated the nitrogenase activity of E. agglomerans , and Pseudomanas sp. On the other hand, the nitrogenase activity of both K. pneumoniae and E. agglomerans was considerably repressed by glyphosate and Roundup, which also inhibited the growth of the bacteria. These chemicals had no effect on the growth of A. lipoferum and Pseudomonas sp., but stimulated their nitrogenase activity.