中文摘要：

利用FACE（free—air carbon dioxide enrichment）技术平台，设常CO2（ambient CO2）和高CO2（elevated CO2，ambient＋200μmol·mol^-1）2个水平和常N（NN，250kg N·hm^-2）和低N（LN，150kg N·hm^-2）2个水平，研究c0，浓度升高对冬小麦（Trhicum aestivumL．）整个生长期生物量和氮（N）吸收的影响。结果表明，CO2浓度升高使冬小麦各部分的生物量平均增加28．3％～44．5％，拔节期增幅最大，达36.8％～91．2％，而且NN处理的生物量增幅比LN处理低。CO2浓度升高不同程度地降低了小麦的N含量，但是增加了N的吸收，在拔节期LN和NN处理下分别增加20.8％和29．2％。CO2浓度升高使小麦在拔节期NN处理的N相对吸收速率增加44．1％。说明在大气CO2浓度升高条件下，小麦会通过生物量的增加固定更多的C，增加对N养分的需求，应着重考虑提高小麦拔节期间的施氮肥水平。

英文摘要：

Increased atmospheric CO2 supply is predicted to alter plant growth and the nutrients level. It is not clear whether the biomass of winter wheat in rice-wheat rotation system is still increased and more nitrogen application is necessary. The biomass and N uptake were studied at two concentration of CO2 [Ambient and Elevated（Ambient ＋ 200 μmol·mol^-1 ）1 and at low and normal nitrogen levels （LN, 150 kg N·ha^-1 and NN, 250 kg N·ha^-1 ） for winter wheat. Growth and N uptake responses of winter wheat at four growth stages were determined. Results showed that the biomass of different parts of wheat increased by 28.3 % - 44.5 % averagely. The response of biomass was significant and the increase degree was the largest at jointing stage. Under LN and NN conditions, the biomass for leave, shoot, ear and root increased significantly by 36.8% ,40.9%, 91.2% and 53.2%, 89.4% ,52.2% ,55.5% and 67.9%, respectively. Moreover, the biomass was increased more at LN than at NN. Nitrogen concentration in each part of wheat was decreased by 3.6% to 25.3 % averagely due to elevated CO2 at both N levels and decreased more at LN than at NN. However, the N uptake was increased significantly by 20.8 % and 29.2% at LN and NN treatment at jointing stage respectively and increased by 1.6% - 32.4% at other growth stages. Under elevated CO2 condition, the relative absorb rate （RAR） was 37.6% at NN more than at LN, but under ambient CO2 condition, it was lower at NN than at LN at jointing stage. On the other hand, RAR was increased by 44.1% at NN under elevated CO2. In conclusion, wheat biomass at different growth stages was increased by elevated CO2 and the effects were extremely significant at jointing stage. The N concentration was decreased more at LN than at NN mad the influence of N level was significant. Since the biomass increased, N uptake by wheat increased and RAR was the largest at jointing stage, the crops should assimilate more carbon and absorb more N from soil under elevated CO2 condition. And maybe jointing sta