Nitrate Reduction in the First Leaf and Roots of Barley Seedlings Grown in Sand and in Culture Solution

Abstract

The in vivo method has been used to determine activity of nitrate reductase in Hiproly and Proctor barley. Differences in activity between the cultivars were small and less than those due to growing conditions. Activity in plants grown in culture solution was greater than that for sand-grown plants, especially in the root The in vivo method gave values for nitrate reductase activity which are less than those found by the in vitro method, and evidence is presented to show that the in vivo method underestimates the rate of formation of organic nitrogen in barley seedlings. It is shown that significant nitrate reductase activity occurs in roots but it is nevertheless concluded that the main site of nitrate assimilation is in the leaves of this material.