【摘要】 以豫麦66号为材料,研究了密度及追氮时期对大穗型小麦旗叶和子粒碳氮代谢的调节效应.结果表明,随着密度增加,旗叶的磷酸蔗糖合成酶(SPS)活性下降,导致标志源端供应能力的可溶性糖(WSC)减少.推迟追氮时期可使SPS活性及WSC含量增加.密度增大导致子粒中蔗糖合成酶(SS)活性及淀粉积累速率降低,推迟追氮时期则使SS活性和淀粉积累速率提高.密度及追氮时期对产量性状有明显的互作效应,增加种植密度可使单位面积成穗数有所提高,但密度过高穗数的增益难以抵偿穗粒数和粒重下降的损失.适当增加密度,配合后期追氮是大穗型小麦实现超高产的有效途径.更多还原

【Abstract】 A study was conducted on the regulating effect of plant density and topdressing time of nitrogen fertilizer on carbohydrate metabolism in flag leaf and grain during grain filling of large ear cultivar of wheat was studied with Yumai 66,a typical large ear cultivar as material.The results showed that the activity of SPS (sucrose phosphate synthase) in flag leaf decreaced with the increase of plant density. Consequently, the content of WSC (water_soluble sugar) in flag leaf, which symbolized assimilate supplying ability of source, decreased.Postponing topdressing time of N fertilizer resulted in increase in the activity of SPS as well as the content of WSC.The activity of SS (sucrose synthase),which is a key in the conversion from sucrose to starch in grain,and the rate of starch accumulation were decreased by high density but could be increased by deferring topdressing time of N fertilizer.There were some interactions between plant density and topdressing time of nitrogen fertilizer on yield characters.Increase in plant density can improve the ear number per hectare,but the increase in benefit of over_density can hardly compensate for the loss of decrease in ear number and grain werght,Therefore,in order to obtain higher yield with large_ear cultivar,higher density and deferring topdressing time of nitrogen fertilizer should be combined.更多还原