水稻主要根系性状对施氮时期反应的品种间差异

以日本晴、武运粳8号、扬稻6号、汕优63为供试材料,设计不施肥、基肥、分蘖肥、促花肥、保花肥等4个不同氮肥施用时期的处理,研究水稻抽穗期主要根系性状对施氮时期反应的品种间差异及其对产量的影响.结果表明:(1)不同穗型品种根系性状差异明显,小穗型品种在每株不定根数、每株不定根总长上具有优势,大穗型品种在每株根干重、

Varietal Differences in Response of Main Root Traits to Nitrogen Application Time in Rice (Oryza sativa L.)

Pot experiment was conducted to investigate the differences in response of main root traits at heading stage and grain yield of four rice varieties, Ribenqing, Wuyunjing 8, Yangdao 6 and Shanyou 63, to nitrogen application time. Nitrogen fertilizer was applied as basal and as top-dressing for tillering, spikelet-promoting and spikelet-sustaining, with no nitrogen application as control. The results showed that: (1) There were significant varietal differences of root traits among different ear-type of varieties. Small-ear type variety presented superiority in number of adventitious roots and total length of the roots per plant, while large-ear type variety had superiority in dry weight of roots per plant and diameter of per adventitious root; (2) Response of number of adventitious roots per plant to nitrogen application time was similar in four varieties,i.e. earlier application was more effective. Basal N and top-dressing significantly increased dry weight and total length of adventitious roots per plant, all varieties involved in this study showed the same tendency, while significant differences in response of that to ear fertilizer were observed among the varieties. There was no significant effect of N application time on diameter of per adventitious; (3) The positive effect of N applied during ear development on dry weight of roots & total length of the roots per plant in large-ear type variety at heading stage was greater than that in small-ear type variety, and spikelet promoting was more effective; (4) As ear-type enlarged and grain yield increased, the number of root traits affecting grain yield increased gradually; (5) Results obtained indicated that improving the development of adventitious roots per plant was important to increase root accumulation at heading stage and grain yield, and all varieties involved in this study showed the same tendency.