Abstract: Based on the concept of the highest population productivity, the yield components and the characteristics of nitrogen absorption and utilization of three types of rice cultivars with low, medium  and high level of the  highest population productivities were investigated at their optimum nitrogen levels. With the increase of the highest population productivity, the total spikelet number increased remarkbly, while the seed setting rate and 1000grain weight showed no significant differences.  The nitrogen accumulation at Nn, heading and maturing stages increased correspondingly as the productivities increased, whereas no significant difference was found at elongation. In order to analyze the nitrogen absorption progress of rice genotypes with different productivities, the whole growth duration was divided into four phases, i.e., from transplanting to critical stage of productive tillering, from critical stage of productive tillering to elongation, from elongation to heading, and from heading to maturing. Results indicated that, the nitrogen accumulation during each period increased typically as the productivity increased during all growth phases except  the phase from critical stage of productive tillering to elongation.Compared with low productivity genotype, the nitrogen translocation amount and nitrogen translocation rate of mediumproductivity genotype increased evidently. However, there   was negligible difference between medium  and high productivity types. Based on the results above, it was concluded that   rice cultivars with the highest population productivity were featured by   rapid nitrogen absorption before Nn,  slow nitrogen absorption  from Nn to elongation, steady nitrogen absorption from elongation to heading, and massive nitrogen absorption from heading to maturing; and a large but not excessive amount of transferred nitrogen from stems and leaves after heading. 

Key words: rice, nitrogenfertilizer, productivity, absorption, utilization

摘要： 以氮肥群体最高生产力的定义为基础，在各基因型最适氮肥水平下，研究了低、中、高3种氮肥群体最高生产力类型粳稻品种的产量结构及其氮素吸收利用特性。结果表明，随着氮肥群体最高生产力递增，总颖花量不断增加，而结实率和千粒重变化不明显。随着氮肥群体最高生产力递增，够苗期、抽穗期和成熟期的氮素积累量逐渐增加，而拔节期无显著差异。各阶段氮素积累量，除够苗至拔节阶段外，其余各阶段均随着氮肥群体最高生产力递增而逐渐增加。与低氮肥群体最高生产力类型相比，中等氮肥群体最高生产力类型氮素转移量和转移率显著增加，而高氮肥群体最高生产力类型氮素转移能力较中等类型相比无显著提高。较之中、低生产力类型，高生产力类型水稻品种具有够苗前氮素积累快，够苗至拔节积累少，拔节至抽穗积累稳，抽穗至成熟积累多，且抽穗后氮素向籽粒转移量大但不过量的特点。 

关键词: 水稻, 氮肥, 生产力, 吸收, 利用