Relationships Between Balance of Nitrogen Supply-Demand and Nitrogen Translocation and Senescence of Different Position Leaves on Rice

摘要

By removing panicles and spikelets, the effects of nitrogen supply-demand balance (NSDB) on nitrogen translocation and senescence of leaves at different positions of the same stem in rice plant were studied. The results showed that under NSDB<0 (CK), nitrogen translocation and senescence of the top 4 leaves was normal. Nitrogen exported from the top leaves (LFT) especially the top 4 leaves decreased remarkably with increase of NSDB, thus, their MDA contents and differences in color (SPAD value) decreased, while the activities of SOD and CAT increased. Under NSDB>0 (panicle removal), N accumulation of the top 4 leaves increased significantly, and the leaf senescence process was delayed. The results also indicated that the color of the 4th LFT was mainly affected by NSDB among the top 4 leaves and was lighter than the 3rd LFT when nitrogen supply was insufficient for the sink need.