Interaction of Combined Nitrogen with the Expression of Root-Associated Nitrogenase Activity in Grasses and with the Development of N(2) Fixation in Soybean (Glycine max L. Merr.).

Peter van, Berkum and Charles, Sloger (1983) Interaction of Combined Nitrogen with the Expression of Root-Associated Nitrogenase Activity in Grasses and with the Development of N(2) Fixation in Soybean (Glycine max L. Merr.). Plant Physiol, 72 (3). pp. 741-745.

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Abstract

Soluble root N concentrations of corn, sorghum, pearl millet, rice, wild rice, and soybeans were determined and related to measurements of nitrogenase activity and changes in availability of combined N to plants. In corn, sorghum, and pearl millet, applications of fertilizer N increased soluble root N concentrations, but root-associated nitrogenase activity was negligible in control and treated plants. Applications of NH4NO3 to rice increased the water soluble root N concentrations and inhibited root-associated nitrogenase activity. In wild rice, root-associated nitrogenase activity was absent during vegetative growth and developed at the reproductive growth stage. The soluble root N concentration decreased progressively as wild rice grew indicating that the availability of combined N in the root environment declined. Therefore, development of nitrogenase activity in wild rice is associated with the change in availability of combined N in the root environment. The development of nitrogenase activity in wild rice was probably not due to colonization of roots by N2-fixing bacteria because most probable numbers of recovery did not significantly vary throughout the plants' growth cycle. In field-grown soybeans with or without fertilizer N application, we also observed a relationship between a decrease in soluble root N concentration and the development of nitrogenase activity.

Item Type: Article
Author Affiliation: United States Department of Agriculture, BARC-West, Beltsville, MD 20705 Nitrogen Fixation and Soybean Genetics Laboratory, BARC-West, Beltsville, MD 20705 1Supported by the United States Department of Agriculture, Agricultural Research Service, Nitrogen Fixation and Soybean Genetics Laboratory, Beltsville, MD, and the Agronomy Department, University of Maryland, College Park, MD, under Cooperative Agreement 58-32U4-3-370. Scientific article No. A-3390, contribution No. 6462 of the Maryland Agricultural Experiment Station, Department of Agronomy, College Park, MD 20742.
Subjects: Plant Protection
Crop Improvement
Divisions: General
Depositing User: Library ICRISAT-InfoSAT
Date Deposited: 01 Apr 2012 11:00
Last Modified: 01 Apr 2012 11:00
Official URL: http://dx.doi.org/10.1104/pp.72.3.741
URI: http://eprints.icrisat.ac.in/id/eprint/4357

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