关键词: 水稻, 硝态氮, 铵态氮, 积累特性, 氮肥调控

Abstract: Based on the field and pot culture experiment of five japonica rice varieties, the content and distribution character of nitrate-N and ammonia-N in the endosperm, their variable trend during the grain filling period and the correlations of N-fertilizer with the enzyme activity of GS among different varieties were analyzed. The results indicated that there was a difference between nitrate-N and ammonia-N content in the mature grain among the rice varieties. The content of ammonia-N is higher than nitrate-N, which both mainly located in rice bran and showed a decline trend from outside to inside. Increasing the N-fertilizer amount led to the increase in the nitrate-N and ammonia-N level by 114.1%~203.0% depending on different varieties; As application of N-fertilizer level raised, each content showed a significant growth. During the filling period, the nitrate-N content in endosperm kept raising until the mature stage, while the accumulation amount of nitrate-N and the content of ammonia-N showed a unimodal curve trend with peak value appearring at the 25th day after heading. Comparing with low nitrate-N content varieties, the daily average growth of nitrate-N was extremely higher than the high content varieties. However, the daily average growth of ammonia-N was lower than the high ammonia-N content varieties at early grain filling stage, but higher at late stage than the low Ammonia-N content varieties. The enzyme activity of GS showed significant difference among different variaties at each stage, having a outstanding positive linear correlation to the content and accumulation rate of ammonia-N and nitrate-N.

Key words: rice, nitrate-N, ammonia-N, accumulation characteristics, N-fertilizer regulation