Influence of ammonium and 2,4-dichlorophenoxy acetic acid on nitrogenase activity in Azospirillum species from rice rhizosphere.
The influence of 2,4-dichlorophenoxy acetic acid (2,4-D) and ammonium on the nitrogenase activity of Azospirillum sp. under normal fixing and low-fixing conditions was evaluated. Nitrogenase activity was substantially stimulated following exposure to 2,4-D at various concentrations up to 5 ppm under normal fixing conditions. A pronounced enhancement in activity occurred with incubation. Significant reduction of the nitrogenase activity occurred in the presence of NH(4+)-N at almost all concentrations of 2,4-D. With incubation the toxic effects of combined nitrogen were alleviated in the presence of higher levels of 2,4-D. Results indicated that the toxic effects of a combination of agrochemicals on nitrogenase in Azospirillum sp. could be mitigated following a long exposure.
Division of Soil Science and Microbiology, Central Rice Research Institute, Cuttack, India.
G K
GK
Patnaik
V R
VR
Rao
D015084:2,4-Dichlorophenoxyacetic Acid / Q000494:pharmacology*; D016949:Azospirillum / Q000201:enzymology* / Q000254:growth & development; D018533:Biomass; D004789:Enzyme Activation / Q000187:drug effects; D009591:Nitrogenase / Q000378:metabolism*; D012275:Oryza / Q000382:microbiology; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*
D000644:Quaternary Ammonium Compounds; D015084:2,4-Dichlorophenoxyacetic Acid; D009591:Nitrogenase