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采用大田试验,以长江中下游地区有代表性的50个早熟晚粳品种为供试材料,设置7个氮肥水平(0、150.0、187.5、225.0、262.5、300.0、337.5 kg/hm2),得出各品种在这7个氮肥水平下出现的群体最高生产力,将该最高生产力定义为氮肥群体最高生产力。根据各品种的氮肥群体最高生产力从高到低将50个品种分为4个产量水平,对不同产量水平品种间各器官的干物质和氮素积累转运、分配等特性进行系统地比较研究。结果表明,抽穗期叶片的氮素含量和氮素积累量以及成熟期叶片和穗的干物质与氮素积累量随产量水平递减逐渐降低;拔节至抽穗阶段茎鞘的干物质积累率以及叶片的干物质和氮素积累速率也随产量水平递减逐渐降低;抽穗至成熟阶段产量大于10.50 t/hm2的水稻品种,茎鞘和叶片的干物质和氮素转运贡献率比其他产量水平低,但穗部干物质和氮素增加量却比其他产量水平高。在满足氮肥群体最高生产力的施肥条件下,拔节至抽穗阶段叶片的干物质、氮素积累速率和产量呈极显著正相关(r=0.635,r=0.539),抽穗至成熟阶段叶片的干物质转运量与产量呈显著负相关(r=-0.360),而叶片的氮素转运量与产量呈显著正相关(r=0.333)。产量大于10.50 t/hm2的水稻品种叶片的干物质和氮素积累与转运比其他产量水平品种在抽穗后表现出明显的优势,穗部物质积累与氮素积累量较高。抽穗后在保持茎鞘适宜的物质和氮素积累量的基础上,提高叶片的物质和氮素积累,进一步加大穗部的物质和氮素积累,是获得高产的保障。
Fifty early-maturing late Japonica rice varieties in the middle and lower reaches of the Yangtze River were used as tested materials to set up seven nitrogenous fertilizers (0,150.0,187.5,225.0,262.5,300.0,337.5 kg / hm2) The maximum productivity of each group appeared in the seven nitrogenous fertilizers, and the highest productivity was defined as the highest productivity of nitrogenous fertilizers. According to the maximum productivity of nitrogenous fertilizer in different varieties, 50 varieties were divided into 4 levels according to the highest productivity. The characteristics of dry matter, nitrogen accumulation, transport and distribution among different organs were systematically compared and studied. The results showed that the nitrogen and nitrogen accumulation of heading leaves and the accumulation of dry matter and nitrogen of leaves and ears decreased gradually with the decline of grain yield at heading stage. The dry matter accumulation of stems and leaves from heading stage to heading stage, The dry matter and nitrogen accumulation rate also decreased with the decreasing of the yield level. The dry matter and nitrogen translocation contribution of stems and sheaths and leaves were lower than those of other rice varieties with the yield of more than 10.50 t / hm2 at heading to mature stage Dry matter and nitrogen levels are higher than other production levels. Dry matter translocation, N accumulation rate and yield were significantly and positively correlated (r = 0.635, r = 0.539), and dry matter translocation from heading to maturing stage under the condition of fertilization satisfying the highest productivity of nitrogenous fertilizer group. There was a significant negative correlation between the amount of nitrogen and yield (r = -0.360), while there was a significant positive correlation between leaf nitrogen translocation and yield (r = 0.333). The dry matter and nitrogen accumulation and translocation of rice cultivars with the grain yield of more than 10.50 t / hm2 showed obvious advantages after heading than those of other grain yielding varieties, with higher accumulation of spike matter and nitrogen accumulation. After heading to maintain the appropriate material and nitrogen accumulation of stem and sheath, based on the increase of leaf matter and nitrogen accumulation, and further increase the ear and nitrogen accumulation of material is to obtain high yield protection.