In vitro studies on the effects of herbicides on the growth of rhizobia.
OBJECTIVE
To study the possible adverse effect of herbicides on nodulation and nitrogen fixation in legumes by affecting the nitrogen-fixing rhizobia.


RESULTS
Experiments were conducted to study the effect of four herbicides (terbutryn/terbuthylazine, trietazine/simazine, prometryn and bentazone) on the growth of nitrogen-fixing pea rhizobia (Rhizobium leguminosarum) in vitro by measuring optical density. Terbutryn/terbuthylazine, trietazine/simazine and prometryn had an adverse effect on the growth of rhizobia whereas bentazone was safe to rhizobia.


CONCLUSIONS
The above herbicides could be used in pea at the recommended rates.


CONCLUSIONS
The adverse effects of herbicides on rhizobia were observed at concentrations not normally expected to occur under field conditions. Further, previously observed adverse effects of these herbicides on nodulation and nitrogen fixation of peas were, possibly, not due to their effects in rhizobia but to their adverse effects on the plant growth itself.
Singh
G
G
School of Agricultural and Forest Sciences, University of Wales, Bangor, Gwynedd, UK. singhguriqba1@rediffmail.com
Wright
D
D
D003470:Culture Media; D006540:Herbicides / Q000494:pharmacology*; D066298:In Vitro Techniques; D009584:Nitrogen / Q000032:analysis; D009586:Nitrogen Fixation / Q000187:drug effects*; D055095:Optics and Photonics; D016961:Rhizobium leguminosarum / Q000187:drug effects* / Q000254:growth & development
D003470:Culture Media; D006540:Herbicides; D009584:Nitrogen