Nitrate Reductase Activity and its Relationship to Accumulation of Vegetative and Grain Nitrogen in Wheat (Triticum aestivum L.)1
- G. L. Eilrich and
- R. H. Hageman2
Nitrate, nitrate reductase activity, soluble protein of total leaf tissue, fresh and dry weight, and reduced nitrogen of total shoot tissue of ‘Arthur’ wheat (Triticum aestivum L.) were measured at intervals throughout the spring growing season in response to three rates of nitrogen [as CA(NO3)2] applied on each of five dates. Yield of straw and grain and their respective concentration of reduced nitrogen at maturity were also obtained.
A positive relationship observed between nitrate content and nitrate reductase activity of the leaf tissue substantiated the dependency of the enzyme activity upon availability of substrate. The increase in nitrate reductase activity in response to added nitrogen was paralleled by an increase in vegetative reduced nitrogen, indicating a casual relationship between enzyme activity and accumulation of reduced nitrogen in the plant. Since translocation of vegetative nitrogen to the grain was uniform across treatments, a significant positive correlation was found between nitrate reductase activity (expressed as moles N ha-1 per season) and grain nitrogen (kg N ha-1) at maturity. Seasonal nitrate reductase also correlated significantly and positively with grain yields (kg ha-l). Similar results were obtained in the preceding season with ‘Ottawa’ and ‘Gage’ wheats, except that the application of nitrogen to Gage caused excessive lodging and thus eliminated the signifiraut correlations between enzyme activity and grain yield and grain nitrogen.
Maintenance of nitrate reductase activity during the reproductive phase in varieties resistant to lodging can increase the yield of grain protein aud prevent the depression of percent grain protein frequently observed when grain yields are high.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © . .