RELATIONSHIP BETWEEN THE AMOUNT OF REDUCED NITROGEN ACCUMULATED IN WINTER-WHEAT SHOOTS AND THE ACTIVITY OF NITRATE REDUCTASE MEASURED IN-SITU

Nitrate reductase activity measured in shoots of winter wheat (Triticu m aestivum cv. Apollo and Soissons) was assessed as an indicator of th e nitrate assimilation rate in plants grown in the field and subjected to various nitrogen nutrition treatments. In N-deficient plants, the nitrate reductase activity was lower than in well fertilized plants an d was an early indicator of nitrogen deficiency. At each stage of stem elongation, there was a constant relationship between the nitrate red uctase activity in the shoots and the quantity of reduced nitrogen acc umulated daily in these organs. This relationship was not affected by the level of nitrogen fertilization.