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Effects of glyphosate on nitrogen fixation of free‐living heterotrophic bacteria
Author(s) -
Santos A.,
Flores M.
Publication year - 1995
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/j.1472-765x.1995.tb01318.x
Subject(s) - azotobacter chroococcum , azotobacter vinelandii , azotobacteraceae , glycine , nitrogen fixation , respiration , glyphosate , biology , bacteria , azotobacter , diazotroph , nitrogen , chemistry , botany , biochemistry , agronomy , nitrogenase , amino acid , genetics , organic chemistry
The effect of the herbicide glyphosate ( N ‐(phosphonomethyl)glycine) on the growth, respiration and nitrogen fixation of Azotobacter chroococcum and A. vinelandii was studied. Azotobacter vinelandii was more sensitive to glyphosate toxicity than A. chroococcum. Recommended dosages of glyphosate did not affect growth rates. More than 4 kg ha ‐1 is needed to find some inhibitory effect. Specific respiration rates were 19.17 mmol O 2 h ‐1 g ‐1 dry weight for A. chroococcum and 12.09 mmol h ‐1 g ‐1 for A. vinelandii. When 20 kg ha ‐1 was used with A. vinelandii , respiration rates were inhibited 60%, the similar percentage inhibition A. chroococcum showed at 28 kg ha ‐1 . Nitrogen fixation dropped drastically 80% with 20 kg ha ‐1 in A. vinelandii and 98% with 28 kg ha ‐1 in A. chroococcum. Cell size as determined by electron microscopy decreased in the presence of glyphosate, probably because glyphosate induces amino acid depletion and reduces or stops protein synthesis.