Cereal Chem 51:330 - 335.  |  VIEW ARTICLE
Nitrate Reductase of Wheat--Its Relation to Nitrogen Fertilization.

H. H. Hernandez, D. E. Walsh, and A. Bauer. Copyright 1974 by the American Association of Cereal Chemists, Inc. 

Nitrate reductase, a rate-limiting enzyme in wheat protein synthesis, was highly influenced by wheat varieties and nitrogen fertilization. Seasonal patterns for three wheat varieties showed that nitrate reductase activities of hard red spring wheat leaf tissues were low in late May (2-3-leaf stage), reached a maximum in early June (boot stage), and diminished rapidly in late June and early July as the wheat began to set seed. Waldron, a tall hard red spring wheat variety, showed lower average reductase activities throughout the growing season than World Seeds 1809 and Bounty 208, two semidwarf hard red spring wheat varieties. Nitrate reductase activity, determined at the boot stage of wheat maturity, showed highly significant positive correlations (1% level of confidence) between wheat grain yield and grain protein yield. Nitrate reductase activity as well as wheat protein yield increased with application of nitrogen fertilizer. Significant protein yield increases were noted with 36 and 64 lb. of nitrogen per acre. However, fertilization with 140 lb. of nitrogen failed to show a significant increase in protein over the 70 lb. per acre of nitrogen fertilizer treatment.