Martin Roberta E, Asner Gregory P, Bentley Lisa Patrick, Shenkin Alexander, Salinas Norma, Huaypar Katherine Quispe, Pillco Milenka Montoya, Ccori Álvarez Flor Delis, Enquist Brian J, Diaz Sandra, Malhi Yadvinder
School of Geographical Sciences and Urban Planning, Arizona State University, Tempe, AZ, United States.
Center for Global Discovery and Conservation Science, Arizona State University, Tempe, AZ, United States.
Front Plant Sci. 2020 Jan 31;10:1810. doi: 10.3389/fpls.2019.01810. eCollection 2019.
Foliar trait adaptation to sun and shade has been extensively studied in the context of photosynthetic performance of plants, focusing on nitrogen allocation, light capture and use chlorophyll pigments and leaf morphology; however, less is known about the potential sun-shade dichotomy of other functionally important foliar traits. In this study, we measured 19 traits in paired sun and shade leaves along a 3,500-m elevation gradient in southern Peru to test whether the traits differ with canopy position, and to assess if relative differences vary with species composition and/or environmental filters. We found significant sun-shade differences in leaf mass per area (LMA), photosynthetic pigments (Chl ab and Car), and δC. Sun-shade offsets among these traits remained constant with elevation, soil substrates, and species compositional changes. However, other foliar traits related to structure and chemical defense, and those defining general metabolic processes, did not differ with canopy position. Our results suggest that whole-canopy function is captured in many traits of sun leaves; however, photosynthesis-related traits must be scaled based on canopy light extinction. These findings show that top-of-canopy measurements of foliar chemistry from spectral remote sensing approaches map directly to whole-canopy foliar traits including shaded leaves that cannot be directly observed from above.
在植物光合作用性能的背景下，人们广泛研究了叶片性状对阳生和阴生环境的适应性，重点关注氮素分配、光捕获与利用、叶绿素色素和叶片形态；然而，对于其他功能重要的叶片性状潜在的阳生 - 阴生二分法了解较少。在本研究中，我们沿着秘鲁南部3500米的海拔梯度，测量了成对的阳生叶和阴生叶中的19个性状，以测试这些性状是否因冠层位置而异，并评估相对差异是否随物种组成和/或环境过滤因素而变化。我们发现叶面积质量（LMA）、光合色素（叶绿素ab和类胡萝卜素）和δC存在显著的阳生 - 阴生差异。这些性状之间的阳生 - 阴生差异在海拔、土壤基质和物种组成变化时保持不变。然而，其他与结构和化学防御相关的叶片性状，以及那些定义一般代谢过程的性状，在冠层位置上没有差异。我们的结果表明，阳生叶的许多性状反映了整个冠层的功能；然而，与光合作用相关的性状必须根据冠层光消光进行缩放。这些发现表明，通过光谱遥感方法对冠层顶部叶片化学的测量可直接映射到整个冠层的叶片性状，包括从上方无法直接观测到的阴生叶。
