中文摘要：

在群体水培条件下，以国内外不同年代育成的常规籼稻代表品种（2001年为88个、2002年为122个）为材料，测定干物重、氮素含量、产量及其构成因素等，采用组内最小平方和的动态聚类方法将供试品种的氮素籽粒生产效率（NUEg）从低到高依次分为A、B、C、D、E和F6种类型，研究不同氮素籽粒生产效率类型品种氮素分配与运转的基本特点。结果表明，供试品种间NUEg的差异很大（244％、325％），A、B、C、D、E和F类品种的平均NUEg，2001年分别为20．51、31．04、35．64、39．46、43．55、50．92gg^-1，2002年分别为24．33、31．61、35．83、39．06、43．51、50．00gg^-1；NUEg高的品种抽穗期、成熟期茎鞘叶中氮素比例小、穗中氮素比例大，成熟期更明显，结实期茎鞘叶氮素运转量大、运转率高；提高结实期茎鞘叶氮素运转量和运转率有利于提高结实期茎鞘叶干物重运转量和经济系数。

英文摘要：

Improving nitrogen use efficiency in crops is of great importance both in crop production and environmental protection. Genetically improving crop varieties has been considered as one of the most economical and effective ways to enhance nitrogen use efficiency （NUE） in crops. Many studies have reported the genotypic differences in NUE for biomass and grain production in rice. Yet, little information in the characteristics of yield components, biomass production and allocation, nitrogen uptake and allocation and structure of root system in rice varieties with higher NUE has been known. In this study, 88 and 122 conventional indica rice cultivars were solution-cultured in 2001 and 2002, respectively. Dry matter weight （including root system, culm and sheath, leaves, panicle）, nitrogen content of different organs, yield and its components were measured. The tested rice cultivars were classified into 6 types （i.e. A, B, C, D, E, and F, A was the lowest, and F was the highest） based on their nitrogen use efficiency for grain output （NUEg） level by the MinSSw method, to study their differences of nitrogen accumulation and nitrogen translocation. Results were as follows： （1） Difference of NUEg of the cultivars used in this study was very large, the averages of NUEg for A, B, C, D, E, and F were 20.51, 31.04, 35.64, 39.46, 43.55, and 50.92 g Grain g^-1 N in 2001, and 24.33, 31.61, 35.83, 39.06, 43.51, 50.00 g Grain g^-1 N in 2002, respectively; （2） In the cultivars with high NUEg level, the nitrogen ratio of culm, sheath and leaf to whole plant was lower, while that of panicle to whole plant was higher at heading stage and especially at ma- turing stage; （3） The amount and rate of nitrogen translocation in culm, sheath and leaf in cultivars with high NUEg level were higher during grain-filling stage; （4） Enhancing the amount and rate of nitrogen translocation in culm, sheath, and leaf during the grain-filling stage could improve dry matter translocation and harvest index.