中文摘要：

为了解弱筋小麦植株衰老特性与籽粒产量及品质形成的关系，选用弱筋小麦扬麦9号，设置不同的氮肥处理，测定和分析了植株生育后期旗叶光合特性和衰老特性及品质指标。结果表明，低氮（180kg／ha）和高氮（240kg／ha）在氮肥比例[基肥：壮蘖肥（5叶期施）：拔节肥（倒3叶施）：孕穗肥（倒1．5叶施）]为7：1：2：0时的两处理生产的籽粒品质均符合国标（GB／T17893—1999）。施氮量180kg／ha、氮肥比例5：1：2：2处理植株生育后期净光舍速率、Rubisco含量、SPAD值、POD和SOD酶活性在品质符合国标的处理中最高，旗叶蔗糖含量高，籽粒转化蔗糖能力强，产量最高；施氮量240kg／ha、氮肥运筹5：1：2：2处理，虽然有效延缓了植株衰老，产量最高，但籽粒品质不符合国标。说明弱筋小麦扬麦9号后期衰老速率快虽有利于降低籽粒蛋白质和湿面筋含量，但不利于产量提高；延缓衰老虽有利于产量提高，但易致品质下降。本试验条件下，弱筋小麦扬麦9号采用施氮量180kg／ha、氮肥运筹5：1：2：2的栽培方式，后期衰老速率适度，有利于品质改善，产量亦较高。

英文摘要：

The experiment was conducted to study the effects of nitrogen application on wheat （Triticum aestivum L. ） plant senescence during the late growth period and its relationship with grain quality. Weak gluten wheat variety Yangmai 9 was cultivated on the experimental field in Yangzhou University. Photosynthetic and senescence characteristics, grain yield and quality were measured. The treatments with low nitrogen （180 kg/ha N）, and high nitrogen （240 kg/ha N ） as well as the proportion of N applied before sowing, at tillering stage, elongation stage and flag leaf stage as 7 ： 1 ： 2 ： 0 could get good grain quality. The treatment with 180 kg/ha N, the proportion of N applied before sowing, at tillering stage, elongation stage and flag leaf stage as 5 ： 1： 2 ： 2 could delay chlorophyll＇s degradation of flag leaves, keep net photosynthetic rate, Rubisco content, the activities of superoxide dismutase （SOD） and peroxidase （POD） at a higher level, and increase sucrose content in flag leaves, which resulted in increase of starch accumulation, grain yield was high among the treatments with good grain quality. The treatment with 240 kg/ha N, the proportion of N applied before sowing, at tillering stage, elongation stage and flag leaf stage as 5 ： 1 ： 2 ： 2 could result in higher yield, but the grain quality was not good. The treatment with fast senescence rate during the late growth period would contribute to reduce grain protein and wet gluten content, which could result in good grain quality, whereas grain yield was low. Under this experiments, the treatment with 240 kg/ha N, the proportion of N applied before sowing, at tillering stage, elongation stage and flag leaf stage as 5 ： 11 ： 12 ： 12 could get good grain quality because of moderate senescence rate, which help weak gluten wheat to obtain better grain quality and yield.