氮肥用量对水稻不同穗位与粒位籽粒灌浆速率的影响

为了探明氮肥用量对不同穗位和粒位籽粒灌浆速率的影响，以‘农大3 号’为试验材料，在磷、钾肥等量的情况下，通过变换氮肥用量，研究了不同穗位和粒位籽粒的灌浆速率。结果表明：不同穗位籽粒的灌浆速率表现为：灌浆高峰期之前，无论是一次枝梗还是二次枝梗粒的灌浆速率均随着穗位下降而降低；灌浆高峰期之后，一次枝梗粒随着穗位的下降而增高，二次枝梗粒除了高肥处理(160~240 kg/hm2)中部>上部>下部外，其他处理均为下部>中部>上部。相同穗位的一、二次枝梗粒的灌浆速率则表现为：灌浆高峰期之前，一次枝梗粒的灌浆速率大于二次枝梗粒；灌浆高峰期以后，二次枝梗粒高于一次枝梗粒。不同穗位和粒位籽粒的灌浆速率呈明显的单峰曲线，灌浆速率随着氮肥用量增加和穗位的下降而降低。

Effects of Nitrogen Fertilizer Amount on Grain Filling Rate of Different Panicle and Grain Positions of Rice

In order to explore the effects of different nitrogen fertilizer amount on grain filling rate of different pinnacle and grain positions, using‘nongda 3’as experimental material, under the condition of the same amount of phosphate and potash fertilizer, by changing the nitrogen fertilizer amount, the grain filling rate of different panicle and grain positions was studied. The results showed that the grain filling rate of different panicle positions was as follows: before grouting peak, whether it was the first branch or the secondary branch grains, the grain filling rate declined along with the lowering of the panicle position. After grouting peak, the filling rate of the first branch grains increased as the panicle position declined, the filling rate of the secondary branch grains was in an order of lower >middle > upper except under high fertilizer treatment (160-240 kg/hm2), which was middle > upper > lower. The grain filling rate of the same panicle position of the first and the secondary branch grains was as follows: before grouting peak, the filling rate the first branch grain was greater than that of the secondary branch grains; after grouting peak, the filling rate of the secondary branch grains was higher than that of the first branch grains. Grain filling rate of different panicle and grain positions showed an obvious unimodal curve, and the grain filling rate decreased with the increase of nitrogen fertilizer amount and the decline of panicle position.