Xu Xiangtao, Medvigy David, Joseph Wright Stuart, Kitajima Kaoru, Wu Jin, Albert Loren P, Martins Giordane A, Saleska Scott R, Pacala Stephen W
Department of Geosciences, Princeton University, Princeton, NJ, 08544, USA.
Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA.
Ecol Lett. 2017 Sep;20(9):1097-1106. doi: 10.1111/ele.12804. Epub 2017 Jul 4.
Leaf longevity (LL) varies more than 20-fold in tropical evergreen forests, but it remains unclear how to capture these variations using predictive models. Current theories of LL that are based on carbon optimisation principles are challenging to quantitatively assess because of uncertainty across species in the 'ageing rate:' the rate at which leaf photosynthetic capacity declines with age. Here, we present a meta-analysis of 49 species across temperate and tropical biomes, demonstrating that the ageing rate of photosynthetic capacity is positively correlated with the mass-based carboxylation rate of mature leaves. We assess an improved trait-driven carbon optimality model with in situLL data for 105 species in two Panamanian forests. We show that our model explains over 40% of the cross-species variation in LL under contrasting light environment. Collectively, our results reveal how variation in LL emerges from carbon optimisation constrained by both leaf structural traits and abiotic environment.
在热带常绿森林中，叶片寿命（LL）的差异超过20倍，但目前尚不清楚如何利用预测模型来捕捉这些差异。当前基于碳优化原则的叶片寿命理论难以进行定量评估，因为不同物种的“衰老速率”存在不确定性，即叶片光合能力随年龄下降的速率。在此，我们对温带和热带生物群落中的49个物种进行了荟萃分析，结果表明光合能力的衰老速率与成熟叶片基于质量的羧化速率呈正相关。我们用巴拿马两个森林中105个物种的原位叶片寿命数据评估了一个改进的性状驱动的碳最优模型。我们发现，在不同光照环境下，我们的模型能够解释超过40%的跨物种叶片寿命差异。总体而言，我们的研究结果揭示了叶片寿命的差异是如何由叶片结构性状和非生物环境共同限制的碳优化过程产生的。
