A paradox of leaf-trait convergence: why is leaf nitrogen concentration higher in species with higher photosynthetic capacity?
A paradox of leaf-trait convergence: why is leaf nitrogen concentration higher in species with higher photosynthetic capacity?
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DOI：
10.1007/s10265-009-0222-z
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发表时间：
2009-05-01
影响因子：
2.8
通讯作者：
Osone, Yoko
中科院分区：
文献类型：
--
作者：
Hikosaka, Kouki;Osone, Yoko
众所周知，在自然生长的植物中，每单位干质量的叶片光合作用（A（质量））与氮浓度（N（质量））正相关。在这篇文章中，我们表明，这种关系是矛盾的，因为，如果其他性状是相同的物种，植物具有较高的A（质量）应该有较低的N（质量），因为稀释的同化碳。为了找到克服稀释效应的因素，我们使用简单的数学模型和文献数据分析了N（质量）-A（质量）关系。我们提出了两个方程来自植物生长模型。将模型预测结果与全球范围内获得的叶片性状谱数据集进行了比较。该模型预测，植物具有较高的A（质量）应该有较高的比氮吸收率在根（SAR），较少的生物量分配给叶，和/或更大的氮分配给叶。根据文献调查，SAR被认为是最可能的因素。如果SAR是维持N（质量）和A（质量）之间正相关关系的唯一因素，则预计SAR的变化远大于A（质量）;鉴于A（质量）变化130倍，SAR可能变化超过2000倍。我们预测，在全球范围内，物种之间的叶和根活动之间存在协调。
It is well known that leaf photosynthesis per unit dry mass (A(mass)) is positively correlated with nitrogen concentration (N(mass)) across naturally growing plants. In this article we show that this relationship is paradoxical because, if other traits are identical among species, plants with a higher A(mass) should have a lower N(mass), because of dilution by the assimilated carbon. To find a factor to overcome the dilution effect, we analyze the N(mass)-A(mass) relationship using simple mathematical models and literature data. We propose two equations derived from plant-growth models. Model prediction is compared with the data set of leaf trait spectrum obtained on a global scale. The model predicts that plants with a higher A(mass) should have a higher specific nitrogen absorption rate in roots (SAR), less biomass allocation to leaves, and/or greater nitrogen allocation to leaves. From the literature survey, SAR is suggested as the most likely factor. If SAR is the sole factor maintaining the positive relationship between N(mass) and A(mass), the variation in SAR is predicted to be much greater than that in A(mass); given that A(mass) varies 130-fold, SAR may vary more than 2000-fold. We predict that there is coordination between leaf and root activities among species on a global scale.