施氮水平对旱秧本田期氮素营养和根系生长和产量形成的影响

以武育粳3号(粳)和汕优63(杂交中籼)为供试材料，研究不同施氮水平对旱秧本田期氮素营养、根系生长和产量形成的影响。结果表明粳稻旱秧本田期植株含氮量、吸氮量、根重和根系伤流强度均随施氮量的增加而增加。杂交稻施氮量过多，生育后期植株含氮量、根系伤流强度下降，吸氮量降低；与湿润秧相比，旱秧拔节前和抽穗后根系活力具有明显优势，植株含氮量高，吸氮量多，但拔节至抽穗根系活力较低；旱秧返青至N-n叶龄期具有明显的分蘖优势，N一n叶龄期之后分蘖消长速度低于湿润秧，茎蘖动态表现出速发稳降的特征；在适宜的施氮水平下，旱秧比湿润秧产量高，在穗粒结构上表现为穗数多、德型大、千粒重偏低的特点，提高千粒重是进一步发挥旱秧增产潜力的关键。

EFFECT OF NITROGEN SUPPLYING LEVEL ON NITROGEN NUTRITION AND THE GROWTH OF ROOTS AND YIELD FORMATION OF DRY NURSERY SEEDLINGS OF RICE IN FIELD

The effect of nitrogen supplying level on nitrogen nutrition and the growth of roots and yield formation of dry nursery seedings of rice in field were studied with the Japonica rice Wuyujing 3 and the mid season indica hybrid rice Shanyou 63 as materials. Results were as follows: The nitrogen content,amount of nitrogen uptaking,root weight and root wount flow of Japonica rice Wuyujing 3 were raised with the increment of nitrogen applying level. Redundant nitrogen applying level would result in lower nitrogen content,root wound flow and amount of nitrogen uptaking at late growth stage of indica hybrid rice. Compared with the moist seedlings, the dry nursery seedlings had higher root activity,nitrogen content and amount of nitrogen uptaking at early and late growth stage and lower root activity at middle growth stage. Dynamic of tillering behaved higher growth rate of tillering from ture green stage to N-n stage and lower growth rate of tilling after N-n stage. Dry nursery seedlings of rice had higher yield with more ears and larger panicle and lower 10 3 grain weight under suitable nitrogen applying level. Raising 10 3 grain weight was key factor to increase yield of dry seedlings.