氮素后移对长江上游机插杂交籼稻库源性状、干物质积累及产量的影响

Effects of Delayed Nitrogen Fertilizer Application on Sink Source Characteristics,Dry Matter Accumulation and Grain yield of Machine-Transplanted Hybrid Indica Rice in Upper Reaches of the Yangtze River

【目的】探明机插杂交籼稻库源关系、干物质生产对氮素后移的响应及其与产量的关系。【方法】以三系杂交水稻渝香203和渝优7109为材料,设置常规施氮处理N_1、不同氮素后移处理N_2、N_3、N_4和对照处理CK,比较叶面积指数(LAI)、粒叶比、干物质积累及其与产量的关系。【结果】较CK处理,施氮处理提高了有效穗数和穗粒数,产量增加。不同氮素处理产量高低顺序为N_4>N_3>N_1>N_2。较N_1处理,不同氮素后移降低了抽穗期LAI,渝优7109的N_4处理降幅达显著水平。较N_1处理,氮素后移处理(N_4)增加渝香203颖花叶比、实粒叶比和粒重叶比分别为10.2%、25.0%和29.3%,增加渝优7109分别为17.4%、18.5%和19.2%。较N_1处理,氮素后移处理(N_4)花前干物质积累量较低,而花后干物质积累和作物生长速率明显增加,群体花后光合优势明显,生物产量显著提高。【结论】氮素后移处理(N_4)通过适度减小机插杂交籼稻花前物质生产而增加花后作物生长速率和生物产量,提高粒叶比,在一定有效穗基础上增加了每穗粒数,从而增加了产量。

[Purpose]To determine the sink source characteristics,dry matter accumulation of machine-transplanted hybrid indica rice as affected by delayed nitrogen(N)fertilizer applications and its relationship with grain yield.[Method]Field experiments,control treatment(CK),conventional fertilization(N1)and delayed nitrogen fertilizer application(N2,N3,N4)were conducted by using two hybrid indica rice varieties Yuxiang203and Yuyou7109under machine-transplantation condition.Grain yield,leaf area index(LAI),grain-leaf ratio,dry matter accumulation and crops growth rate were measured in this study.[Results]Compared with CK,N fertilizer treatments significantly increased panicles and spikelets per panicle,and consequently improved grain yield.The grain yield of different N fertilizer treatments showed that N4>N3>N1>N2.Compared with N1,delayed N fertilizer applications decreased LAI in heading stage,and with significant reduction of LAI for Yuyou7109.Compared with N1,ratio of spikelet number to leaf area,ratio of filled grain number to leaf area and ratio of grain weight to leaf area of delayed N fertilizer applications(N4)were increased by10.2%,25.0%and29.3%for Yuxiang203,and by17.4%,18.5%and19.2%for Yuyou7109,respectively.Compared with N1,delayed N fertilizer applications(N4)lowered dry matter accumulation before flowering,but increased biomass production and photosynthetic material production quite higher after flowering,which owed to higher crop growth rate after flowering.[Conclusion]Delayed N fertilizer applications(N4)controlled biomass production before flowering,increased crop growth rate and dry mater accumulation after flowering,improved grain-leaf ratio,increased spikelets per panicle,and thus,improved grain yield of machine-transplanted hybrid indica rice.