Nitrogen economy of the main shoot of field-grown barley (Hordeum vulgare L.) I. Dry weight, duration, and nitrate content in different organs

Abstract

The main shoot of field-grown Jyoti barley (Hordeum vulgare L.) grown at 40 kg ha^-1 was separated into different organs at various stages of growth and development. Changes in fresh and dry weights and duration for which the parts remained metabolically active (green) were recorded. Weight duration (gram × day), a factor contributing to total NO^-₃ reduction of each organ, was calculated. The dry matter percentage increased in the successively formed laminae and sheaths. The weight duration of the different components viz. internodes, spike (excluding the grains), laminae, and sheaths, respectively were 40.2, 10.5, 21.8, and 17.8. Nitrate content (µmol g^-1 dry wt.) was high in the initially formed organs and declined in the successively formed ones. In the laminae, there was a sharp fall after achieving maximal values except for the flag lamina where the changes in NO^-₃ content were marginal over a fairly long period. The ear components had low NO₃^- concentration. Total NO^-₃ content (µmol) in the main shoot showed peaks at 49, 84, and 118 d after sowing.