分期施氮与CO_2浓度升高对小麦光合及其物质积累和产量的互作效应

Interactive Effect of Split Application of Nitrogen and CO_2 Elevation on Photosynthesis,Matter Accumulation and Yield of Winter Wheat

采用开顶式气室和盆栽方法,以冬小麦品种‘小偃22’为材料,探讨了分期施氮与CO2浓度升高对小麦抽穗期和灌浆中期旗叶光合、地上部物质积累和产量的互作效应.结果显示:(1)不施氮条件下CO2浓度升高对小麦旗叶叶绿素含量(SPAD)和可溶性蛋白含量、光合能力、地上部花后干物质和氮素累积量、籽粒产量的影响不明显(P>0.05)或产生显著负效应;在施氮(300mg/kg土)条件下各指标均不同程度增加,且大多数达到显著水平.(2)与氮肥全部基施相比,分期施氮时CO2浓度升高使灌浆期旗叶光合能力、地上部花后干物质和氮素累积以及产量增加的幅度较大,其中以播前、返青期和孕穗期施氮比例为5∶3∶2时最明显.研究表明,适当分期施氮可能更有利于发挥CO2浓度升高对冬小麦的增产作用.

A pot experiment was conducted to investigate the interactive effect of split application of nitro- gen and CO2 elevation on photosynthesis, dry matter and nitrogen accumulation at heading and middle grain filling stage,and grain yield of winter wheat with open top chambers （OTCs） of wheat variety ＇Xiaoyan 22＇. The results showed that CO2 enrichment had no or negative effect on SPAD value, soluble protein con- tent and photosynthetic ability of flag leaf,dry matter and nitrogen accumulation of shoot after anthesis, and grain yield under no nitrogen application, but under nitrogen addiction （300 mg/kg soil）, the indexes increased to some extent, and its effects were mostly significant at 0.05 probability level. Compared with all-based application of nitrogen,CO2 elevation could increase photosynthetic ability at grain-filling stage, dry matter and nitrogen accumulation of shoot after anthesis, and grain yield under nitrogen split applica- tion,especially under nitrogen application with the ratio of 5 ： 3 ： 2 at before sowing,re-greening and boo- ting stages. It was suggested that CO2 elevation would preferably increase grain yield of winter wheat under proper split application of nitrogen.