Diffuse solar radiation and canopy photosynthesis in a changing environment
Diffuse solar radiation and canopy photosynthesis in a changing environment
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DOI：
10.1016/j.agrformet.2021.108684
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发表时间：
2021-10-20
影响因子：
6.2
通讯作者：
Robson, T. Matthew
中科院分区：
文献类型：
--
作者：
Durand, Maxime;Murchie, Erik H.;Robson, T. Matthew
植物接受的阳光受到云层和污染的影响。未来云层覆盖的变化将因地区而异，而由于野火、化石燃料燃烧和工业污染，预计全球气溶胶浓度将继续上升。云和气溶胶增加了入射太阳辐射的漫射分数，改变了光谱组成，两者都会影响光合作用和陆地生态系统的生产力。因此，作为准确预测未来全球碳同化的一部分，需要对树冠和树叶水平的过程如何响应这些变化进行评估。为了回顾这些过程及其影响：首先，我们讨论了云和气溶胶对穿过大气的太阳辐射的影响的物理基础；其次，我们考虑了直接和漫射辐射是如何被植物树冠及其叶子吸收和传输的；最后，我们评估了树冠和生态系统水平上对光合作用的影响。由于不同的散射，云或气溶胶下的光谱成分分别向更短或更长的波长移动，光生物学将在大气层面受到影响。由于扩散率增加而引起的小气候和辐射光谱组成的变化还取决于冠层结构和生理特征的适应，如叶面积指数、定向和丛生。再加上光能利用效率的提高，这使得漫射太阳辐射对树冠光合作用的影响成为一个多层次的现象，需要进行实验测试来捕捉这些复杂的相互作用，这些相互作用将确定它是否会像目前陆地-地表模型预测的那样，在碳同化方面产生持续的增强。
The sunlight received by plants is affected by cloudiness and pollution. Future changes in cloud cover will differ among regions, while aerosol concentrations are expected to continue increasing globally as a result of wildfires, fossil fuel combustion, and industrial pollution. Clouds and aerosols increase the diffuse fraction and modify the spectral composition of incident solar radiation, and both will affect photosynthesis and terrestrial ecosystem productivity. Thus, an assessment of how canopy and leaf-level processes respond to these changes is needed as part of accurately forecasting future global carbon assimilation. To review these processes and their implications: first, we discuss the physical basis of the effect of clouds and aerosols on solar radiation as it penetrates the atmosphere; second, we consider how direct and diffuse radiation are absorbed and transmitted by plant canopies and their leaves; and finally, we assess the consequences for photosynthesis at the canopy and ecosystem levels. Photobiology will be affected at the atmospheric level by a shift in spectral composition toward shorter or longer wavelengths under clouds or aerosols, respectively, due to different scattering. Changes in the microclimate and spectral composition of radiation due to an enhanced diffuse fraction also depend on the acclimation of canopy architectural and physiological traits, such as leaf area index, orientation, and clumping. Together with an enhancement of light-use efficiency, this makes the effect of diffuse solar radiation on canopy photosynthesis a multilayered phenomenon, requiring experimental testing to capture those complex interactions that will determine whether it produces the persistent enhancement in carbon assimilation that land-surface models currently predict.