Photosynthesis responds quickly to changes in light, increasing with incoming photosynthetic photon flux density (PPFD) until the leaves become light saturated. This instantaneous response to PPFD, which is widely studied and incorporated into models of photosynthesis, is overlaid on non-instantaneous photosynthetic changes resulting from the acclimation of plants to average PPFD over intermediate timescales of a week to months \(\left( {\overline {{\mathrm{PPFD}}} } \right)\). Such photosynthetic light acclimation is not typically incorporated into models, due to the lack of observational constraints. Here, we use eddy covariance observations from globally distributed and automated sensor networks, along with photosynthesis estimates from nine terrestrial biosphere models (TBMs), to quantify and assess photosynthetic acclimation to light in natural environments. We also use recent theoretical developments to incorporate light acclimation in a TBM. Our results show widespread light acclimation of ecosystem photosynthesis. On average, a 1 μmol m⁻² s⁻¹ increase in \(\overline {{\mathrm{PPFD}}} _{{\mathrm{10}}}\) (ten-day average PPFD) leads to a 0.031 ± 0.013 μmol C m⁻² s⁻¹ increase in the maximum photosynthetic assimilation rate (A_max), with croplands having stronger acclimation rates than grasslands and forests. Our analysis shows that the TBMs examined either neglect or substantially underestimate light acclimation. By updating a TBM to include photosynthetic acclimation, successfully reproducing the \(\overline {{\mathrm{PPFD}}} _{{\mathrm{10}}}\)–A_max relationship, we provide a robust method for the incorporation of photosynthetic light acclimation in future models.

光合作用对光的变化做出快速响应，并随着传入的光合作用光子通量密度（PPFD）的增加而增加，直到叶片变得光饱和为止。对PPFD的这种瞬时反应已得到广泛研究，并已纳入光合作用模型中，它覆盖了植物在一周至数月的中间时间段内适应平均PPFD所产生的非瞬时光合作用变化\（\ left（{\ overline {{\ mathrm {PPFD}}}} \ right）\）。由于缺乏观测约束，这种光合光适应性通常不纳入模型。在这里，我们使用来自全球分布和自动化的传感器网络的涡动协方差观测结果，以及来自九个陆地生物圈模型（TBM）的光合作用估计，来量化和评估自然环境中光的光合适应性。我们还使用了最新的理论发展成果，将光适应性纳入了TBM。我们的结果表明，生态系统的光合作用具有广泛的光适应性。平均而言，\（\ overline {{\ mathrm {PPFD}}} __ {{\ mathrm {10}}} \\）（十天平均PPFD）增加1μmolm ^-2  s ^-1会导致0.031 ±0.013μmolC m ^-2  s ^-1最大光合作用率增加（A _max），其中耕地的适应性强于草地和森林。我们的分析表明，TBM检查的结果是忽略或严重低估了光照适应性。通过更新TBM包括光合适应，成功地再现\（\划线{{\ mathrm {PPFD}}} _ {{\ mathrm {10}}} \） -甲_最大的关系，我们提供用于掺入稳健的方法模型中光合光适应的研究