Abstract: The field and pot experiments were conducted to study the effect of the allocating ratio of N-fertilizer on nitrogen uptake, grain amino acid contents and grain yield of two-line hybrid rice. For two-line hybrid rice (early season),the grain yield at the treatment of N application of 180 kg/hm², 30% N for panicle development(applied at the flag leaf appearing in the main culm)and 70% N for basal fertilizer was the highest, and both increased by 6.2% compared to the treatments of the same N application (180 kg/hm² ) with 10% N for panicle development and N application of 120 kg/hm 2 with 30% N for panicle development. For late season, the N allocating ratio getting the highest yield at the N application of 210 kg/hm² was 30% N for panicle development, too. The result of three different N application levels showed that, the order of N recovery and agronomic efficiency was 30%>20%>10%, N use efficiency was 30%<20%<10%, at the treatment of different N allocating ratios. The essential amino acid contents in brown rice under the N allocating ratio of 30% for panicle development and 70% for basal fertilizer was increased by 0.09―0.38 percent point compared with other treatments of different N allocating ratios. Among the essential amino acid contents increased, Leu and Ile contents were increased the most, followed by the Lys content. The yield of brown rice, the accumulated amount of amino acids and essential amino acids under this treatment was also increased by 5.4%-27.5%, 5.4%-30.4% and 15.1%-36.0% compared with other treatments, respectively.

Key words: two-line hybrid rice, fertilizer, nitrogen, amino acid, grain yield, nutrient use efficiency

摘要： 在田间和盆栽条件下研究了穗肥氮施用比例对两系杂交水稻氮素吸收、籽粒氨基酸含量和产量的影响。两系杂交早稻施N 180 kg/hm2，30%作穗肥、70%作基肥的稻谷产量最高，比施N 180 kg/hm2 10%作穗肥和施N 120 kg/hm2 30%作穗肥两个处理均增产6.2%。晚稻在施N 210 kg/hm2条件下，仍以30%作穗肥处理的稻谷产量最高。3个施氮量平均，氮肥利用率和农学效率均表现为30%作穗肥＞20%作穗肥＞10%作穗肥，氮肥利用效率表现为30%作穗肥＜20%作穗肥＜10%作穗肥。与其他氮素穗肥比例处理比较，氮肥30%作穗肥、70%作基蘖肥的分配方案能提高稻米必需氨基酸含量0.09~0.38个百分点，其中又以亮氨酸和异亮氨酸增加较多，赖氨酸次之；且稻米产量、总氨基酸积累量和必需氨基酸积累量分别增加5.4%～27.5%、5.4%～30.4%、15.1%～36.0%。

关键词: 两系杂交稻, 施肥, 氮素, 氨基酸, 稻谷产量, 养分利用效率