title: Nitrogenase activity in wheat seedlings bearing para-nodules induced by 2,4-dichlorophenoxyacetic acid (2,4-D) and inoculated with Azospirillum.
abstract: Nitrogenase activity (C2H2 reduction) was demonstrated in seedlings of wheat roots bearing para-nodules induced by 2,4-dichlorophenoxyacetic acid (2,4-D) and inoculated with Azospirillum brasilense. Increased nitrogenase activity was observed in inoculated para-nodulated seedlings as compared to inoculated roots not treated by 2,4-D under the conditions of assay used. 2,4-D had no stimulating effect on plant ethylene production in the absence of acetylene. When inoculation was performed with a Nif-mutant of A. brasilense, no ethylene production was detected. It was also shown that the energy source required for nitrogenase activity was supplied by the host plant.
authors.affiliation: Department of Agricultural Chemistry, University of Sydney, Australia.
authors.forename: A M
authors.initials: AM
authors.lastname: Zeman
authors.forename: Y T
authors.initials: YT
authors.lastname: Tchan
authors.forename: C
authors.initials: C
authors.lastname: Elmerich
authors.forename: I R
authors.initials: IR
authors.lastname: Kennedy
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000494:pharmacology*; D000114:Acetylene / Q000378:metabolism; D015806:Azospirillum brasilense / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D005030:Ethylenes / Q000378:metabolism; D066298:In Vitro Techniques; D008854:Microscopy, Electron; D009586:Nitrogen Fixation / Q000502:physiology; D009591:Nitrogenase / Q000378:metabolism*; D013559:Symbiosis / Q000502:physiology*; D014908:Triticum / Q000187:drug effects / Q000201:enzymology / Q000382:microbiology*
chemical_list: D005030:Ethylenes; D015084:2,4-Dichlorophenoxyacetic Acid; D009591:Nitrogenase; D000114:Acetylene