Nitrogen Distribution and Dry Matter Accumulation in Oilseed Rape (Brassica napus L.) as Influenced by N Nutrition

Abstract

AbstractA greenhouse experiment was conducted to study N distribution and dry matter accumulation in oilseed rape (Brassica napus L. cv. Callypso) in relation to N supply. Three levels of N supply (30, 100 or 170 ppm N) were tested as treatments. Stem and leaf dry weights increased at higher N fertility up to 170 ppm N but root dry weight did not respond to N. Dry matter yield during the vegetative phase was seriously depressed by N deficiency. Most of the plant dry matter was accumulated in the lower segments of the stem and roots. Dry weights of stem and axillary branches increased significantly as N supply increased up to 100 ppm N. Although hull dry weight increased with N supply up to 100 ppm N, seed dry weight did not respond to N. High root N concentration was maintained at 100 or 170 ppm N; but declined as plants advanced in age. N content of leaf and stem also declined with time. Leaf growth was particularly responsive to N fertility and N was mobilised from the older to the younger leaves over time. Nitrogen content of hulls and seeds increased significantly with N supply but N was translocated from the vegetative into the generative organs or from older into younger tissues during pod development. There is need for proper N fertility management in order to achieve successful rape production.