Plant responses to elevated CO2 concentration at different scales:: leaf, whole plant, canopy, and population
Plant responses to elevated CO2 concentration at different scales:: leaf, whole plant, canopy, and population
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DOI：
10.1007/s11284-005-0041-1
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发表时间：
2005-05-01
影响因子：
2
通讯作者：
Hirose, T
中科院分区：
文献类型：
--
作者：
Hikosaka, K;Onoda, Y;Hirose, T
CO2浓度升高会增强植物的光合作用和生长，但这种增强受到氮素有效性的强烈影响。在这篇文章中，我们总结了我们的研究，植物对CO2浓度升高的反应。叶片的光合能力不仅取决于叶片氮含量，而且还取决于氮在叶片内的分配。在虎杖中，氮在光合组分中的分配不受CO2浓度升高的影响，但在季节之间发生变化。由于氮分配的改变导致不同的CO2依赖的光合速率，增强光合作用升高CO？秋天比夏天大。每单位面积的叶质量（LMA）在CO2浓度升高的植物中增加。这种增加被认为是由于积累了不用于植物生长的碳水化合物。然而，与一个敏感的分析的增长模型，我们建议，在LMA的增加是有利的增长，在CO2浓度升高补偿叶氮浓度每单位质量的减少。CO2浓度升高对生殖产量的提高往往小于营养生长的预期。在加拿大苍耳，CO2浓度升高并没有增加种子产量，但营养生长增加了53%。由于种子的氮浓度在不同的CO2水平下保持不变，我们认为，氮的可用性限制在CO2水平升高的种子生产。我们发现，植物冠层叶面积的发展受到强烈的限制，而不是由CO2的氮的可用性。在自由空气CO2浓度升高的稻田中，叶面积指数（LAI）随氮素有效性的增加而增加，但不随CO2浓度升高而变化。我们确定了最佳的叶面积指数，以最大限度地提高冠层光合作用，并证明了冠层光合作用的提高，CO2浓度升高是在高比低氮可用性。我们还研究了竞争的不对称性在一个年龄均匀，单种立场在CO2浓度升高的个人。光采集（每单位地上质量获得的光）和利用（每单位获得的光的光合作用）进行了计算，为每一个人在station.Elevated CO2，增强光合作用和生长的高大的优势，这减少了光的可用性较短的下属，从而增加了大小的不平等的立场。
Elevated CO2 enhances photosynthesis and growth of plants, but the enhancement is strongly influenced by the availability of nitrogen. In this article, we summarise our studies on,plant responses to elevated CO2. The photosynthetic capacity of leaves depends not only on leaf nitrogen content but also on nitrogen partitioning within a leaf. In Polygonum cuspidatum, nitrogen partitioning among the photosynthetic components was not influenced by elevated CO2 but changed between seasons. Since the alteration in nitrogen partitioning resulted in different CO2-dependence of photosynthetic rates, enhancement of photosynthesis by elevated CO? was greater in autumn than in summer. Leaf mass per unit area (LMA) increases in plants grown at elevated CO2. This increase was considered to have resulted from the accumulation of carbohydrates not used for plant growth. With a sensitive analysis of a growth model, however, we suggested that the increase in LMA is advantageous for growth at elevated CO2 by compensating for the reduction in leaf nitrogen concentration per unit mass. Enhancement of reproductive yield by elevated CO2 is often smaller than that expected from vegetative growth. In Xanthium canadense, elevated CO2 did not increase seed production, though the vegetative growth increased by 53%. As nitrogen concentration of seeds remained constant at different CO2 levels, we suggest that the availability of nitrogen limited seed production at elevated CO2 levels. We found that leaf area development of plant canopy was strongly constrained by the availability of nitrogen rather than by CO2. In a rice field cultivated at free-air CO2 enrichment, the leaf area index (LAI) increased with an increase in nitrogen availability but did not change with CO2 elevation. We determined optimal LAI to maximise canopy photosynthesis and demonstrated that enhancement of canopy photosynthesis by elevated CO2 was larger at high than at low nitrogen availability. We also studied competitive asymmetry among individuals in an even-aged, monospecific stand at elevated CO2. Light acquisition (acquired light per unit aboveground mass) and utilisation (photosynthesis per unit acquired light) were calculated for each individual in the stand. Elevated CO2, enhanced photosynthesis and growth of tall dominants, which reduced the light availability for shorter subordinates and consequently increased size inequality in the stand.