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Abstract
Differences of nitrogen efficiency of oilseed rape (Brassica napus L.) cultivars and their physiological properties were studied in a pot experiment, and the ratio of seed yield with no nitrogen supplied to that with normal nitrogen supply was adopted as a nitrogen efficiency coefficient. Results showed that the nitrogen efficiency coefficient determined for eight oilseed rape cultivars varied from 0.37 to 0.69, the ratio of nitrogen uptake amounts per plant, nitrogen transfer velocity from stems and leaves to seeds, and nitrogen physiological efficiency of oilseed rape cultivars under nitrogen stressed condition differed from with normal nitrogen supply. The higher the nitrogen efficiency of a cultivar, the higher the ratio of N uptake in no nitrogen to with N supplied. Under low nitrogen-supplying conditions, high nitrogen efficiency cultivars had longer roots, more lateral roots, higher amounts of reuse of nitrate from stem and leaves, and higher nitrate reductase activities in leaves.
ACKNOWLEDGMENTS
This study was supported by the National Natural Science Foundation of China (Grant No. 30971860), Key Project of National Natural Science Foundation in Hunan (07JJ3074), The Industry Technology System of Rapeseed, Agriculture Ministry of China (nyctx-00509), State Plan for High-Tech Research and Development (863 Plan, Grant No. 2006BAD21B030), Major Science and Technology Projects of Hunan (2009FJ1006-1 and 2009FJ1006-3), Innovation and Technology Fund Supports Projects Institution of Higher Learning in Hunan Province (09K049).