Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia.
School of Biological Sciences, University of Bristol, Bristol, UK.
Nat Commun. 2022 Aug 25;13(1):5005. doi: 10.1038/s41467-022-32545-0.
Tropical forests take up more carbon (C) from the atmosphere per annum by photosynthesis than any other type of vegetation. Phosphorus (P) limitations to C uptake are paramount for tropical and subtropical forests around the globe. Yet the generality of photosynthesis-P relationships underlying these limitations are in question, and hence are not represented well in terrestrial biosphere models. Here we demonstrate the dependence of photosynthesis and underlying processes on both leaf N and P concentrations. The regulation of photosynthetic capacity by P was similar across four continents. Implementing P constraints in the ORCHIDEE-CNP model, gross photosynthesis was reduced by 36% across the tropics and subtropics relative to traditional N constraints and unlimiting leaf P. Our results provide a quantitative relationship for the P dependence for photosynthesis for the front-end of global terrestrial C models that is consistent with canopy leaf measurements.
热带雨林通过光合作用每年从大气中吸收的碳 (C) 比任何其他类型的植被都多。全球热带和亚热带森林的碳吸收受到磷 (P) 限制的影响。然而，这些限制所依据的光合作用-P 关系的普遍性存在疑问，因此在陆地生物圈模型中没有得到很好的体现。在这里，我们证明了光合作用和基础过程对叶片 N 和 P 浓度的依赖性。P 对光合作用能力的调节在四大洲是相似的。在 ORCHIDEE-CNP 模型中实施 P 限制，与传统的 N 限制和无限制的叶片 P 相比，热带和亚热带地区的总光合作用减少了 36%。我们的研究结果为全球陆地 C 模型前端的光合作用对 P 的依赖性提供了一种定量关系，与冠层叶片测量结果一致。
