Abstract
Symbiotic associations of bean plants (Phaseolus vulgaris L. cv. Blue Lake) and Rhizobium phaseoli strain 127K17 were treated with the Hill reaction inhibitor bentazon (3-isopropyl-1 H-2,1,3-benzothiadiazin-4-(3H)-one-2,2-dioxide). Plants receiving foliar and root treatments of 1.8 kilograms per hectare bentazon were assayed at 6 hour intervals for N2-fixing capacity by measuring C2H2-dependent C2H4 production and H2 evolution and for CO2 exchange rates. In foliar treated plants greatest measured inhibition of CO2 exchange rates and N2-fixing capacity occurred 6 and 12 hours after treatment, respectively. In root-treated plants maximum inhibition of both processes was delayed by 6 hours, and was less severe than in foliar treated plants. Nitrogen-fixing capacity and CO2 exchange rate recovered to control levels in all plants. Application of higher rates of bentazon resulted in greater inhibition of CO2 exchange rate and N2-fixing capacity. Inhibition of the two processes was positively correlated (r = 0.985). The results indicate that inhibition of N2-fixing capacity was not caused by bentazon directly, but indirectly through limiting the availability of photosynthate to support root nodule activity.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bethlenfalvay G. J., Phillips D. A. Effect of Light Intensity on Efficiency of Carbon Dioxide and Nitrogen Reduction in Pisum sativum L. Plant Physiol. 1977 Dec;60(6):868–871. doi: 10.1104/pp.60.6.868. [DOI] [PMC free article] [PubMed] [Google Scholar]