直播种植模式下水稻剑叶光合、强弱势籽粒灌浆特性及产量的氮素调控

为探讨不同施氮水平对水稻剑叶光合、籽粒灌浆特性和产量的影响。以生育期较短的‘新稻567’、‘新稻568’和‘新科稻31’为试验材料,在直播种植模式下,设置3个施氮水平0、255、300 kg/hm²,分别测定抽穗后剑叶光合速率、强弱势籽粒灌浆速率和产量等指标,研究氮肥调控水稻产量的生理机制。结果表明,随着施氮量的增加,3个品种产量均呈先增加后降低的趋势;高效叶面积率和粒叶比表现为中氮水平较高,高氮水平较低。灌浆期剑叶光合速率呈先增加后降低趋势,不同氮肥处理间基本表现为中氮处理高于高氮处理;强弱势籽粒灌浆速率在整个灌浆期内呈开口向下的抛物线趋势,不同氮肥处理间的差异在灌浆盛期至灌浆中后期较大,表现为无氮和中氮处理高于高氮处理,灌浆末期处理间差异较小。产量与灌浆期剑叶光合速率呈正相关关系,与强弱势籽粒灌浆速率在灌浆初期呈负相关在灌浆中后期呈正相关关系。适度的氮肥施用量有利于提高直播水稻高效叶面积率、粒叶比,增加剑叶光合速率、强弱势籽粒灌浆速率,从而促进水稻高产。

Direct Seeding Mode of Rice: Nitrogen Regulation of Flag Leaf Photosynthesis, Superior and Inferior Grains Filling Characteristics and Yield

The objective was to reveal to raise yield effective ways of the reasonable regulation of rice leaf photosynthesis and superior and inferior grain filling rate . The research was to investigate the effects of different nitrogen application on leaf photosynthetic ,grain filling characteristics and yield, and to explore the relationship between yield and leaf photosynthetic rate and grain filling rate under direct seeding mode in rice, and provide a theoretical basis for rice high yield cultivation of direct seeding . The field was taking xindao 567, xindao 568 and xinkedao 31 as test materials to determine leaf photosynthetic rate, grain filling rate and yield after heading under three treatments of 0, 255 and 300 kg/.ha nitrogen. The results showed that the yield of three varieties were increased first and decreased later with the increase of nitrogen. High rate of leaf area and grain leaf ratio showed higher level under middle nitrogen, and lower under high nitrogen level. The flag leaf photosynthetic rate at grain filling stage was first increased and then decreased trend, which was higher under middle nitrogen than that of high nitrogen treatment. Superior and inferior grain filling rate was open downward parabolic trend at the whole grain filling period, which of different nitrogen treatments was higher between the peak and middle-late grain filling stage. The grain filling rate of zero and middle nitrogen was higher than high nitrogen treatment, and the difference was small at later grain filling stage. Yield was positively correlated with flag leaf photosynthetic rate during grain filling stage, and negatively correlated with grain filling rate at early grain filling stage, and positively correlated at middle and late stage. The appropriate amount of nitrogen fertilizer is beneficial to improve the efficient leaf area rate, grain leaf ratio, and increase flag leaf photosynthetic rate and grain filling rate. It can be created good photosynthetic traits, improved rice photosynthetic capacity and grain filling ability to promote the rice high yield through the regulation of appropriate nitrogen fertilizer under direct seeding mode in rice.