两种熟相小麦籽粒建成期的氮素吸收与转运

Nitrogen Uptake and Translocation During Grain Formation of Two Wheat Cultivars with Contrasting Maturity Appearance

在稳定小麦籽粒蛋白质含量前提下，小麦开花后的吸氮能力可能成为再高产的限制因素之一。为此，在盆栽条件下研究了2种小麦在籽粒建成期对氮素的吸收及营养体内氮的转运规律。结果表明，莱州953具有以下特征：①后期吸氮潜力高，并能有效地输入籽粒，减轻了籽粒蛋白质合成对叶片氮的需要。在开花期供氮条件下尤其明显。②叶片氮含量高且输出高峰较迟。③籽粒前期氮积累慢，后期加快。④根系积累氮素较多，可能有助于延缓整株的衰老。以上几个方面均可能与绿熟的形成有关，但因果关系尚需进一步探讨。2类品种各有其限制性，本试验中莱州953分蘖成穗率低导致单株产量较低。鲁麦14号虽然单株产量较高，但开花期叶叶片氮浓度低，开花后氮吸收少且叶片氮素输出快，可能成为其产量潜力增加的的重要限制因素。

The potential of post-anthesis nitrogen uptake in wheat may become a limiting factor with the increasing grain yield providing that the grain protein content stablises. In the present study, two wheat cultivars, a stay-green one (cv. Lai-953) and a yellow-mature one (cv. Lu-14), were employed to investigate the potential of nitrogen uptake after anthesis as related to the nitrogen translocation from the vegetative organs to seeds. It is showed that the stay-green cultivar had the following characters: ①MDre nitrogen was absorbed after anthesis, especially when additional nitrogen were applied at anthesis, stage, which may be helpful to redtice the demand of nitrogen exporting from leaves for grain protein accumulation. ②Nitrogen content in leaves was higher and declined slowly during the first two weeks of grain filling. ③Nitrogen accumulation in grain was slow during the first two weeks after anthesis. ④Ample storage of nitrogen in roots might contribute to the delayed senescence of the whole plant. The relationship among these factors needs to be explored thoroughly. The yield of Lai-953 was limited by less ears per plant which lead to the lower total grain weight per plant. As to Lu-14, the yield potential might be limited by low N content in leaves at anthesis, less N uptake and quick export of leaf N during grain filling, though the total grain weight per plant was higher in this experiment.