超级中籼杂交水稻氮素积累利用特性与物质生产

在大田条件下比较了5个超级稻品种和对照汕优63的物质生产及氮素吸收利用特性。结果表明, 超级稻物质生产与积累优势始于拔节期, 并随着生育进程而扩大, 抽穗以后的干物质量积累优势明显。超级稻对氮素的吸收积累总量达196.5 (184.3~200.8) kg hm^-2,较对照的176.5 kg hm^-2增加20.0 kg hm^-2, 其中拔节前与对照相当, 拔节至抽穗期增加9.2 kg hm^-2, 抽穗至抽穗后25 d增加4.9 kg hm^-2 , 抽穗后25 d至成熟期增加4.3 kg hm^-2。氮素吸收速率拔节至孕穗阶段达最高峰, 超级稻为3.68 (3.44~3.96) kg N hm^-2 d^-1, 对照为3.55 kg N hm^-2 d^-1; 孕穗期以后吸氮速率随着生育进程而逐渐下降, 抽穗25 d以后, 对照基本不具再吸收能力, 而超级稻仍具一定吸收能力(0.36 kg N hm^-2 d^-1)。超级稻生育中、后期氮素吸收利用能力的提高促进了抽穗和灌浆结实期植株特别是叶片含氮率的提高, 孕穗期、抽穗期、抽穗后25 d、成熟期叶片含氮率均与相应生育阶段的干物质积累量显著相关, 与最终总生物量极显著相关。超级稻在10.5 t hm^-2产量水平下的百千克籽粒吸氮量在1.83 kg左右。

Dry-Matter Accumulation and Nitrogen Absorption and Utilization in Middle-Season Indica Super Hybrid Rice

The field experiment was conducted in 2006 to research the difference of characteristics of dry matter accumulation and nitrogen uptake and utilization between five super rice cultivars and the control—Shanyou 63. The dry matter production of middle-season indica super hybrid rice was started from the beginning of elongation stage, and with the rice growing, the comparative advantage of dry matter accumulation was gradually speeded up. The middle-season indica super hybrid rice had apparent advantage in biomass accumulation after heading. Total amount of nitrogen absorption was 196.5 (184.3–200.8) kg ha^-1 in super rice cultivar, which was 20.0 kg ha^-1 higher than that of control. The amount of nitrogen absorption of middle-season indica super hybrid rice cultivar corresponded to that of control before jointing stage, however, increased 9.2 kg ha^-1 more than that of CK from jointing stage to heading stage, 4.9 kg ha^-1 more than that of CK at 25 days after heading stage, and 4.3 kg ha^-1 more than that of CK from 25 days after heading stage to maturity. The Nitrogen uptake rate reached its peak at booting stage, and the middle-season indica super hybrid rice was 3.68 (3.44–3.96) kg N ha^-1 d^-1 while the control was 3.55 kg N ha^-1 d^-1. And then, the nitrogen uptake was slower and slower after booting stage, and at 25 days after heading and at maturing stage, the N-uptake rate was 0.36 kg N ha^-1 d^-1 in super rice, whereas it was almost zero in the control. It can be seen that middle-season indica super hybrid rice held high N rate in the leaf blade after heading stage, which was beneficial to chlorophyll contents stability and photosynthate accumulation so that the super high yield of the rice could become true. The result also showed that the super hybrid rice should absorb about 1.83 kg N per hundred kilogram grain when its yielding level was 10.5 t ha^-1.