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利用开顶式气室对春小麦进行了一个生长季的CO2 倍增盆栽实验 ,土壤水分控制为 3个水平 (分别为田间持水量 (FWC)的 80 %、6 0 %、4 0 % )。结果显示 ,CO2 倍增显著提高小麦的光合速率。但在相同的CO2 测定浓度下 ,生长在加倍CO2 浓度下的小麦的光合速率比当前CO2 浓度下小麦低 2 2 %。高CO2 浓度显著促进小麦生长 ,相对增加幅度在适宜水分下最大 ,为 14 .8%。 80 %FWC水分条件下高CO2 使植株的干重 /高度比增加 15 .7%。高CO2 条件下 ,小麦的蒸腾速率降低、累积耗水量减少、水分利用效率 (WUE)提高 ,WUE的提高幅度在适宜水分下最大 ,为30 %。干旱 (40 %FWC)使小麦地上干重和WUE在当前CO2 条件下分别降低 72 %和 19% ,加倍CO2 条件下降低幅度较大 ,分别为 76 %和 2 3%。根据以上结果得出结论 :(1)高CO2 条件下 ,小麦的光合速率、地上生物量和水分利用效率提高 ;(2 )植物长期生长于高CO2 浓度导致光合能力降低 ;(3)高CO2 对植物侧向生长的促进作用大于垂直生长 ,即高CO2 下植株将相对粗壮 ;(4)高CO2 对植物的生态效应依赖于土壤水分 ,在适宜水分下相对较大 ;(5 )在未来高CO2 条件下 ,干旱引起的减产和水分利用效率减低幅度将会更大。
The CO2 multiplication pot experiment was conducted on spring wheat in open-air chamber for one growing season. Soil moisture was controlled at 3 levels (80%, 60% and 40% of FWC). The results showed that CO2 doubling significantly increased the photosynthetic rate of wheat. However, the photosynthesis rate of wheat grown at doubled CO2 concentration was 22% lower than the current CO2 concentration at the same CO2 concentration. High CO2 concentration significantly promoted the growth of wheat, the relative increase of which was the largest under suitable water, which was 14.8%. High CO2 under 80% FWC moisture increased plant dry weight / height ratio by 15.7%. Under high CO2, the transpiration rate of wheat decreased, the accumulated water consumption decreased and the water use efficiency (WUE) increased. The maximum increase of WUE was 30% under suitable water. Drought (40% FWC) decreased wheat ground dry weight and WUE by 72 and 19%, respectively, under the current CO2 conditions, with significant reductions of 76% and 23%, respectively, under double CO2 conditions. Based on the above results, the conclusions are as follows: (1) Under high CO2, the photosynthetic rate, aboveground biomass and water use efficiency of wheat increased; (2) The long-term plant growth at high CO2 concentration led to the decrease of photosynthetic capacity; (3) (4) The ecological effect of high CO2 on plants depends on soil moisture, which is relatively large under suitable water; (5) In the future, high CO2 Under the conditions, drought reduction and water use efficiency reduction will be even greater.