RESPONSE OF ERIOPHORUM-VAGINATUM TO ELEVATED CO2 AND TEMPERATURE IN THE ALASKAN TUSSOCK TUNDRA
RESPONSE OF ERIOPHORUM-VAGINATUM TO ELEVATED CO2 AND TEMPERATURE IN THE ALASKAN TUSSOCK TUNDRA
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DOI：
10.2307/1939271
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发表时间：
1987-04-01
期刊：
影响因子：
4.8
通讯作者：
OECHEL, WC
中科院分区：
文献类型：
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作者：
TISSUE, DT;OECHEL, WC
北极地区的小型温室被用来在环境二氧化碳(340u.L/L)、高二氧化碳(510u.L/L或680u.L/L)或高二氧化碳和4度的环境中保持以阴道毛细管藻为主的苔原10wk。高于环境温度(680µL/L，环境+4度)的摄氏度。这些处理代表了大气二氧化碳和温度的当前水平，以及下个世纪的预测水平。在3wk内，维持在高二氧化碳水平下的植物表现出其光合作用速率的生理调整，从而使生长在环境和高二氧化碳水平下的植物在各自的生长CO2浓度下具有相似的光合作用速率。生长在高二氧化碳水平下的植物光合作用能力的下降似乎不是由于气孔关闭或最终产物抑制。其他可能的机制还没有被探索。在苔原湿润环境下，不同处理间蒸腾速率和水分利用效率无明显差异。叶片的相对生长速率和生长的季节模式也没有改变，这表明在正常环境条件下，成熟分蘖的生长不受温度或碳水化合物的限制。然而，在CO2浓度升高的情况下，新的分蘖产量显著增加，这表明在这片莎草中增加二氧化碳的长期影响可能是产生更多的新分蘖，而不是增加现有分蘖的大小或生产力。我们的结果与这样的观点是一致的，即河蟹在野外的生长更多地受到营养供应的限制，而不是光合作用。我们进一步认为，光合作用速率反映了汇的活性。因此，很难确定生长速率和光合作用速率之间的因果关系。
Small greenhouses were used in the arctic to maintain Erioporum vaginatum-dominated tussock tundra for 10 wk at ambient CO2 (340 .mu.L/L), elevated CO2 (510 or 680 .mu.L/L), or elevated CO2 and 4.degree. C above ambient temperature (680 .mu.L/L, ambient + 4.degree.). These treatments represent present levels of atmospheric CO2 and temperature, and those predicted for the next century. Within 3-wk, plants maintained at elevated CO2 exhibited a physiological adjustment of their photosynthetic rate so that plants grown at ambient and elevated CO2 levels had similar photosynthetic rates at their respective growth CO2 concentrations. The reduction in photosynthetic capacity for plants grown at elevated CO2 levels did not appear to be due to stomatal closure or end-product inhibition. Other possible mechanisms were not explored. Transpiration rate and water use efficiency did not differ among treatments in the generally wet environment of tussock tundra. Relative leaf growth rate and the seasonal pattern of growth were also unaltered, suggesting that the growth of mature tillers is not, under normal ambient conditions, limited by temperature or carbohydrate. However, new tiller production was significantly increased at elevated CO2, suggesting that the long-term effect of CO2 enhancement in this sedge may be the production of a greater number of new tillers rather than an increase in the size or productivity of existing tillers. Our results are consistent with the notion that growth of Eriophorum vaginatum in the field is more limited by nutrient supply than by photosynthesis. We further suggest that photosynthetic rates reflect the sink activity. It is therefore very difficult to assign cause and effect between growth rates and photosynthetic rates.