稻穗不同部位籽粒的结实能力

Fertilities of Spikelets at Different Positions of the Panicle in Rice (Oryza sativa L.)

1988 1991年,在群体水培、大田及盆栽条件下,采用籼、粳水稻品种,分年度设计水分、氮肥、磷肥、遮光等39种处理,以改变根量、根系活力、颖花数、抽穗前贮藏碳水化合物的含量、抽穗后光合产物积累量及籽粒受容活性等,研究稻穗上、中、下部一、二次枝梗籽粒的结实能力。结果表明:同穗不同部位一、二次枝梗籽粒饱粒率均有上部>中部>下部(Ⅰ),上部>下部>中部(Ⅱ), 中部>上部>下部(Ⅲ),中部>下部>上部(Ⅳ),下部>中部>上部(Ⅴ),下部>上部>中部(Ⅵ)等六种类型;同穗不同部位一、二次枝梗籽粒千粒重均有Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅵ等五种类型;证明迟开颖花的结实能力可优于早开颖花;认为通过栽培措施调节灌浆速度、灌浆持续时间和颖花根活量等就可调节不同部位籽粒的饱粒率和粒重,继而使不同部位籽粒的饱粒率和粒重在穗中的顺序发生变化。

The experiments were carried out in 1988-1991 under hydroponical , field and pot cultural conditions with indica, japonica rice cultivars and hybrid rice as the materials. By treatments of different rates of water supply, nitrogen fertilizer, phosphorous fertilizer and shading, various levels of root amount, root activity, spikelet number, storage carbohydrates content before heading and net photosynthates acummulation after heading were attained, in order to analyse the spikelet fertilities of the upper, middle and lower parts of primary and secondary branches of the panicle. The results showed that, Fulfilled grain percentages of the spikelets in primary and secondary branches at different positions in the panicle could be classified into 6 categories, i.e., upper > middle >lower(Ⅰ), upper > lower >middle(Ⅱ), middle > upper >lower(Ⅲ), middle > lower > upper(Ⅳ), lower > middle >upper(Ⅴ), lower > upper > middle(Ⅵ). The 1000-grain weights of the different primary and secondary branch parts could be classified into 5 categories (i.e., Ⅰ,Ⅱ,Ⅲ,Ⅳ and Ⅵ). These proved that the inferiority of the late flowered spikelets could be shifted, their fertilities could be higher than those flowered early. It was concluded that by regulating the average grain filling rate, grain filling period and spikelet root activity, the ripening percentage and grain weight could be changed, and consequently the order of ripening percentage and grain weight in different parts of the panicle could be altered.