冬小麦冠层不同叶层和茎鞘氮素与籽粒品质关系的研究

 以优质品种中优 950 7和普通品种京冬 8号为材料 ,研究了冬小麦叶片、茎鞘氮素的垂直分布、输出量及其与主要品质指标间的关系。结果表明 ,叶片含氮量随冠层层次降低而降低 ,垂直梯度分明 ,处理间、不同生育时期梯度大小不同。茎鞘氮素垂直梯度不如叶片明显 ,中优 950 7梯度大小、生育期内变化不如京冬 8号显著。中优950 7灌浆盛期至蜡熟阶段叶片和茎鞘氮素输出量分别比京冬 8号高 2 9.9%和 76.3 %。灌浆期京冬 8号冠层中下部形成较大梯度利于其品质的改善 ,中优 950 7开花期上部层次形成大的梯度 ,灌浆期上部层次叶片、中下部层次茎鞘含氮量高均利于其籽粒蛋白质的积累。两种类型品种品质的改善较多地依赖后期植株氮素的输出。京冬 8号叶片氮素对籽粒品质的形成作用明显 ,而叶片和茎鞘氮素对中优 950 7籽粒品质的形成具有同等重要的作用

Studies on the Nitrogen State of Leaf, Culm and Sheath at Different Layers in Canopy and Their Relationship with Grain Quality in Winter Wheat

Vertical distribution of nitrogen in canopy, nitrogen e xporting amount and their influences on grain quality of winter wheat were studi ed. Two cultivars, differing in quality, Jingdong8, a common cultivar, Zhongyou 9507, a high quality cultivar were investigated. The results showed that leaf ni trog en decre ased with leaf layer lowering. There existed different vertical gradients of nit rogen among all treatments during growth stages. There was no apparent vertical gradient in culm and sheath in Zhongyou9507 compared with that of leaf and Jing dong8. Zhongyou9507 had more exporting amount of nitrogen in leaf, culm and shea th than that of Jingdong8 from middle-filling to waxening stage, especially the nitrogen exporting amount in culm and sheath, which was higher than that of Jingdong8 in almost all growth stages. Higher vertical gradients of nitrogen in Jingdong8 at anthesis had disadvantages on its grain quality. But higher vertica l gradients of nitrogen between middle and lowers layers of Jingdong8 at filling stage improved its grain quality. Higher vertical gradients of nitrogen in upper layer at anthesis and upper layer leaf and middle layer culm and sheath at fill ing stage had advantages on grain protein accumulation of Zhongyou9507. There wa s a positive correlation between nitrogen exporting amount in leaf and grain qua lity at later stage in two cultivars. The positive correlation between culm and sheath and grain quality of Jingdong8 emerged at the phase from anthesis to earl y-filling, and that emerged at two phases from anthesis to early-filling and f rom middle-filling to waxening of Zhongyou9507. Leaf nitrogen did more contribu tion to the grain quality of Jingdong8. Higher protein of Zhongyou9507 relied on the nitrogen status in its leaf, culm and sheath. Nitrogen in culm and sheath p layed more important role on the grain quality of Zhongyou9507 than that of Jing dong8.