This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Web of Science (36) Citing Articles via Google Scholar Google Scholar Articles by Nelson, D. R. Articles by Porter, C. A. Search for Related Content PubMed PubMed Citation Articles by Nelson, D. R. Articles by Porter, C. A. Agricola Articles by Nelson, D. R. Articles by Porter, C. A.

Articles

Role of Nitrogen Assimilation in Seed Development of Soybean

Monsanto Company, St. Louis, Missouri 63167

A nondestructive acetylene reduction assay for nitrogenase activity of soybean (Glycine max L. Merr) field plots is presented. Plots consisted of 120 x 150 x 30 centimeter boxes containing 65 plants. The plants were grown in a medium grade sand under controlled nutrient, moisture, and root temperature conditions. Acetylene at a concentration of 10 milliliters per liter was circulated through manifolds in the chambers; equilibration required 5 minutes, and activity was linear with time. Optimum growth and assay environments resulted in activity of 70 micromoles ethylene per plant per hour. Plant development and yield were comparable to soil-grown companion plots.

The well accepted hypothesis that developing seeds deprive the nodules of carbohydrate was not substantiated. The nondestructive acetylene reduction profile did not decline until 30 days after the onset of seed development (R-5). This result was consistent with reports from the literature which indicated that 60% of seasonal nitrogen was fixed after R-5. Further, a high correlation shown between integrated seasonal acetylene reduction and yield (r = 0.999) suggested a cooperative relationship between the roots and shoot. A reduction in source:sink ratio (60% defoliation) after R-5 had no effect on acetylene reduction. This showed that neither an increase in sink demand by the pods nor a carbon shortage during podfill decreased dinitrogen fixation. A conceptual model relating seed growth with carbon and nitrogen assimilation is proposed.

This article has been cited by other articles:

				J. R. Freeborn, D. L. Holshouser, M. M. Alley, N. L. Powell, and D. M. Orcutt Soybean Yield Response to Reproductive Stage Soil-Applied Nitrogen and Foliar-Applied Boron Agron. J., November 1, 2001; 93(6): 1200 - 1209. [Abstract] [Full Text] [PDF]

				T.R. Sinclair, L.C. Purcell, V. Vadez, R. Serraj, C.A. King, and R. Nelson Identification of Soybean Genotypes with N2 Fixation Tolerance to Water Deficits Crop Sci., November 1, 2000; 40(6): 1803 - 1809. [Abstract] [Full Text] [PDF]