A theory of plant function helps to explain leaf-trait and productivity responses to elevation.
A theory of plant function helps to explain leaf-trait and productivity responses to elevation.
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DOI：
10.1111/nph.16447
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发表时间：
2020-01
期刊：
影响因子：
--
通讯作者：
Yunke Peng;K. Bloomfield;I. Prentice
中科院分区：
文献类型：
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作者：
Yunke Peng;K. Bloomfield;I. Prentice
一些出版物研究了沿着亚马逊-安第斯山脉的样带的叶性状和碳循环的变化，该样带跨越3.5 km的海拔和16℃的年平均温度。光合能力以前被证明是增加，随着海拔的升高，温度下降，抵消酶动力学效应。然而，由于光照减少，初级生产下降。我们的目的是预测叶性状和生产梯度的第一原则，使用已发表的数据来测试一个新兴的理论，光合特性和初级生产取决于最佳的驯化和/或适应环境。我们重新分析了210个物种在25个站点公布的数据，拟合线性关系的预测和观察到的光合特性和初级生产的海拔。随着海拔的升高，叶片内/外CO2比值（χ）降低，羧化能力（Vcmax）和电子传递能力（Jmax）增加。叶片氮含量随海拔升高而增加的原因是增加了Vcmax和叶质量单位面积。叶和土壤磷共变，但海拔控制后，没有营养指标占任何额外的光合特性的变化。据预测，初级生产力将随着海拔的升高而下降。这种分析统一叶和生态系统的观测在一个共同的理论框架。初级生产对温度的不敏感性被证明是光合特性优化的结果。
Several publications have examined leaf-trait and carbon-cycling shifts along an Amazon-Andes transect spanning 3.5 km elevation and 16℃ mean annual temperature. Photosynthetic capacity was previously shown to increase as temperature declines with increasing elevation, counteracting enzyme-kinetic effects. Primary production declines, nonetheless, due to decreasing light availability. We aimed to predict leaf-trait and production gradients from first principles, using published data to test an emerging theory whereby photosynthetic traits and primary production depend on optimal acclimation and/or adaptation to environment. We re-analysed published data for 210 species at 25 sites, fitting linear relationships to elevation for both predicted and observed photosynthetic traits and primary production. Declining leaf-internal/ambient CO2 ratio (χ) and increasing carboxylation (Vcmax ) and electron-transport (Jmax ) capacities with increasing elevation were predicted. Increases in leaf nitrogen content with elevation were explained by increasing Vcmax and leaf mass-per-area. Leaf and soil phosphorus covaried, but after controlling for elevation, no nutrient metric accounted for any additional variance in photosynthetic traits. Primary production was predicted to decline with elevation. This analysis unifies leaf and ecosystem observations in a common theoretical framework. The insensitivity of primary production to temperature is shown to emerge as a consequence of the optimization of photosynthetic traits.