水稻大穗形成机理的研究——穗肥施用时期对每穗颖花分化、退化和现存数的影响

FORMATION OF LARGE PANICLE IN RICE ——EFFECT OF NITROGEN APPLICATION TIME ON THE DIFFERENTIATED, RETROGRADED AND SURVIVED SPIKELETS PER PANICLE

在盆栽条件下以武育粳２号、盐粳２号两粳稻品种为材料，系统分析了不同时期施用穗肥对每穗颖花分化数、退化数和现存数及其相互关系的影响。结果表明，（１）促进一、二次颖花分化作用最大的时期分别是抽穗前３６、３１ｄ，对全穗颖花分化数促进作用最大的时期为抽穗前３１ｄ；（２）抽穗前４６～６ｄ施用穗肥均可显著降低颖花退化率，以抽穗前１６～２１ｄ施用穗肥对颖花退化数、退化率的降低幅度最大。一、二次颖花退化数分别与一、二次枝梗退化数呈极显著线性正相关关系，ｒ分别为０．９９２８＊＊、０．９９３７＊＊；（３）抽穗前４６～１１ｄ施用穗肥可显著增加每穗颖花现存数，以抽穗前３１ｄ处理每穗颖花现存数的增加幅度最大。每穗颖花现存数与每穗颖花分化数呈极显著线性正相关关系（ｒ＝０．９１５４＊＊）；（４）不同时期施用穗肥对抽穗期单茎干物重影响较小，对每克干物质形成现存颖花能力影响较大。

Japonica rice varieties Wuyujing 2 and Yanjing 2 were planted in pot for analyzing the effect of nitrogen application time on differentiated, retrograded, survived spikelet numbers per panicle and their relationships Results showed that the differentiated spikelet number on primary branch per panicle was increased most when nitrogen applicated at 36 days before heading (DBH), for the differentiated spikelets on secondary branch, 31 DBH, for the differentiated spikelets per panicle, 31 DBH Nitrogen applicated at 46 to 6 DBH were all effective in decreasing the retrograded spikelet number per panicle and the retrograding spikelet percentage, the most efficient time was 16 to 21 DBH The retrograded spikelet numbers on primary and secondary branch were significantly correlated to the retrograded primary and secondary branch numbers with correlation coefficient 0 9928 ** and 0 9937  , respectively The survived spikelet numbers per panicle were significantly increased when nitrogen applicated at 46 to 11 DBH The most effective time was 31 DBH The survived spikelet number was significantly correlated to the differentiated spikelets per panicle with corelation coefficient 0 9154  Dry matter per stem at heading was subjected little to the nitrogen application date The ratio of survived spikelets to dry matter at heading was greatly affected