不同氮肥水平下结实期灌溉方式对水稻弱势粒灌浆及产量的影响

摘要

[目的]旨在阐明氮肥和灌溉方式对水稻产量、籽粒灌浆及生理特性的影响.[方法]以大穗型品种甬优2640和中穗型品种淮稻5号为供试材料进行盆钵试验,大田育秧移栽后设置3种氮肥水平,即0 N(不施氮)、MN(2 g N/盆)、HN(4 g N/盆);抽穗至成熟期设置3种灌溉方式,即CI(保持水层灌溉)、WMD(轻干湿交替灌溉, 土壤水势 -15 kPa时复水)、WSD(重干湿交替灌溉, 土壤水势 -30 kPa时复水).[结果]在CI下,两个品种产量均以MN水平最高;WMD处理下,两个品种产量均以HN水平最高,但与MN下差异不显著,WSD处理下两个品种产量均以HN最高;而在籽粒灌浆上,两个品种强势粒的灌浆速率和最终粒重在各个水氮处理间无显著差异,弱势粒的灌浆速率和最终粒重在良好水势条件CI和轻度水分胁迫WMD下,分别在0 N和MN水平下表现较优;但在重度水分胁迫WSD下,0N水平表现最低,HN最高,但与MN差异不显著.以上都表明产量与弱势粒的灌浆在水氮间存在着明显的交互作用.在品种间,大穗型籼粳杂交稻甬优2640弱势粒灌浆速率及粒重都低于中穗型常规粳稻淮稻5号,其产量优势主要源自较高的每穗粒数.最后,WMD+MN处理下有较高的氮肥利用率,较少的施氮量获得较高的产量,达到节水节氮增产的效果,其次也增加了根系生理活性和叶片光合性能,非结构性碳水化合物(NSC)转运率,促进了地上部的生长发育,同时也加强了物质运转,促进了灌浆中后期弱势粒籽粒的充实,最终达到产量增加的目的,成为本研究最佳水氮运筹方式.%[Objective]To investigate the effects of water and nitrogen application on yield and grain filling, [Method]an indica/japonica hybrid Yongyou 2640 with large-panicle and a japonica inbred Huaidao 5 with mid-panicle were grown in pots. After field seedling nursing then transplanting to pots, we designed three N rates, namely 0N (0 g N/pot), medium N level(MN, 2 g N/pot), and high N level(HN, 4 g N/pot), and three irrigation regimes post-anthesis consisting of conventional irrigation (CI, soil water potential was kept at 0 kPa), alternate wetting and moderate drying irrigation (WMD, rewatered when soil water potential reached -15 kPa), and alternate wetting and severe drying irrigation (WSD, rewatered when soil water potential reached -30 kPa). [Result] In the CI regime, MN showed the highest grain yield; in the WMD regimes, however, there was no significant difference in grain yield between MN and HN. Furthermore, in the WSD regime, grain yield under HN was the highest. In terms of grain filling, the superior spikelets present no significant difference in grain filling rate and final grain weight compared with all water-nitrogen treatments; Inferior spikelets performs better in grain filling rate and final grain weight at 0N and MN under CI and WMD regimes. However, in the WSD regime, 0N led to the lowest while HN showed the highest grain filling and final grain weight, but not significantly different to MN. The above results showed that there was an obvious interaction between water and nitrogen. Among the varieties,grain filling rate and grain weight of inferior spikelets of indica/japonica hybrid Yongyou 2640 were lower than that of japonica inbred Huaidao 5,and the advantage of grain yield of Yongyou 2640 stemed from higher spikelet number per panicle. Finally, in the WMD+MN treatment, there was a higher nitrogen efficiency, creating higher grain yield with less nitrogen, and achieving the purpose of water and nitrogen saving. Secondly, it also eahanced the activity of root and leaves, improving the non-structural carbohydrate(NSC) remobilization, which promoted the upground biomass development and dry matter translocation in order to strengthen the inferior spikelets filling to induce an increase in grain yield. Therefore, it turns out to be the best water-nitrogen management in this research.