Jiang Mingkai, Caldararu Silvia, Zhang Haiyang, Fleischer Katrin, Crous Kristine Y, Yang Jinyan, De Kauwe Martin G, Ellsworth David S, Reich Peter B, Tissue David T, Zaehle Sönke, Medlyn Belinda E
Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia.
Max Planck Institute for Biogeochemistry, Jena, Germany.
Glob Chang Biol. 2020 Oct;26(10):5856-5873. doi: 10.1111/gcb.15277. Epub 2020 Jul 31.
Phosphorus (P) is an essential macro-nutrient required for plant metabolism and growth. Low P availability could potentially limit plant responses to elevated carbon dioxide (eCO ), but consensus has yet to be reached on the extent of this limitation. Here, based on data from experiments that manipulated both CO and P for young individuals of woody and non-woody species, we present a meta-analysis of P limitation impacts on plant growth, physiological, and morphological response to eCO . We show that low P availability attenuated plant photosynthetic response to eCO by approximately one-quarter, leading to a reduced, but still positive photosynthetic response to eCO compared to those under high P availability. Furthermore, low P limited plant aboveground, belowground, and total biomass responses to eCO , by 14.7%, 14.3%, and 12.4%, respectively, equivalent to an approximate halving of the eCO responses observed under high P availability. In comparison, low P availability did not significantly alter the eCO -induced changes in plant tissue nutrient concentration, suggesting tissue nutrient flexibility is an important mechanism allowing biomass response to eCO under low P availability. Low P significantly reduced the eCO -induced increase in leaf area by 14.3%, mirroring the aboveground biomass response, but low P did not affect the eCO -induced increase in root length. Woody plants exhibited stronger attenuation effect of low P on aboveground biomass response to eCO than non-woody plants, while plants with different mycorrhizal associations showed similar responses to low P and eCO interaction. This meta-analysis highlights crucial data gaps in capturing plant responses to eCO and low P availability. Field-based experiments with longer-term exposure of both CO and P manipulations are critically needed to provide ecosystem-scale understanding. Taken together, our results provide a quantitative baseline to constrain model-based hypotheses of plant responses to eCO under P limitation, thereby improving projections of future global change impacts.
磷（P）是植物新陈代谢和生长所需的一种必需大量营养素。低磷有效性可能会限制植物对二氧化碳浓度升高（eCO₂）的响应，但对于这种限制的程度尚未达成共识。在此，基于对木本和非木本植物幼体同时进行二氧化碳和磷处理的实验数据，我们对磷限制对植物生长、生理和形态对eCO₂响应的影响进行了荟萃分析。我们发现，低磷有效性使植物对eCO₂的光合响应减弱了约四分之一，导致与高磷有效性条件下相比，对eCO₂的光合响应降低，但仍为正值。此外，低磷分别限制了植物地上、地下和总生物量对eCO₂的响应，幅度分别为14.7%、14.3%和12.4%，相当于高磷有效性条件下观察到的eCO₂响应幅度大约减半。相比之下，低磷有效性并未显著改变eCO₂诱导的植物组织养分浓度变化，这表明组织养分灵活性是低磷有效性条件下生物量对eCO₂响应的重要机制。低磷显著降低了eCO₂诱导的叶面积增加14.3%，这与地上生物量响应情况相似，但低磷并未影响eCO₂诱导的根长增加。木本植物对低磷对地上生物量对eCO₂响应的衰减作用比非木本植物更强，而具有不同菌根关联的植物对低磷和eCO₂相互作用表现出相似的响应。这项荟萃分析突出了在捕捉植物对eCO₂和低磷有效性响应方面关键的数据空白。迫切需要进行基于田间的实验，对二氧化碳和磷处理进行长期暴露，以提供生态系统尺度的理解。综上所述，我们的结果提供了一个定量基线，以限制基于模型的关于磷限制条件下植物对eCO₂响应的假设，从而改进对未来全球变化影响的预测。
