The Leaf Economics Spectrum Constrains Phenotypic Plasticity Across a Light Gradient

Abstract

The leaf economics spectrum (LES) characterizes multivariate correlations that confine the global diversity of leaf functional traits onto a single axis of variation. Although LES is well established for traits of sun leaves, it is unclear how well LES characterizes the diversity of traits for shade leaves. Here, we evaluate LES using the sun and shade leaves of 75 woody species sampled at the extremes of a within-canopy light gradient in a subtropical forest. Shading significantly decreased the mean values of LMA and the rates of photosynthesis and dark respiration, but had no discernable effect on nitrogen and phosphorus content. Sun and shade leaves manifested the same relationships among N mass , P mass , A mass , and R mass (i.e., the slopes of log-log scaling relations of LES traits did not differ between sun and shade leaves). However, the difference between the normalization constants of shade and sun leaves was correlated with functional trait plasticity. Although the generality of this finding should be evaluated further using larger datasets comprising more phylogenetically diverse taxa and biomes, these findings support a unified LES across shade as well as sun leaves.

A whole‐plant economics spectrum including bark functional traits for 59 subtropical woody plant species

“…As indicators of plant strategies (Violle et al, 2007;Westoby et al, 2002;Zhao, Ali, et al, 2016), functional traits affect (or at the very least reveal) life history and plant distribution characteristics (Díaz et al, 2004;Engelbrecht et al, 2007) involving trade-offs affecting plant growth and survival. For example, the leaf economics spectrum (LES) combines a series of interrelated leaf functional traits to quantitatively obtain pervasive plant resource trade-offs (Chen et al, 2021;Pan et al, 2020;Wright et al, 2004) that can predict the dynamics of community composition and the feedback of ecosystem functions (Chen et al, 2020;Reich et al, 1998;Wright et al, 2005). The LES has been extended to include the characteristics of wood (Chave et al, 2009) and later those of plant organs other than leaves (Kong et al, 2015;Roumet et al, 2016).…”

Rapid estimation of photosynthetic leaf traits of tropical plants in diverse environmental conditions using reflectance spectroscopy

“…Indeed, we empirically showed that our spectra approach was accurate even when applied to new species or sites. We also think that our PLSR models could be applied more generally in the tropics, as there is a strong coordination among the traits of leaves and their function; known as the leaf economic spectrum [ 68 , 69 ]. This strong coordination could explain why a PLSR model trained on a sufficient number of species and conditions allowed that PLSR model to be sufficiently general for other species of the same biome [ 29 , 55 ].…”

Prediction of photosynthetic light‐response curves using traits of the leaf economics spectrum for 75 woody species: effects of leaf habit and sun–shade dichotomy

“…Furthermore, G max increased close to 1:1 with K and RR, whereas q Lcp and A max had less than proportional allometric relationships. Interestingly, scaling relationships between LES traits also have been shown to be similar in leaves at different canopy positions (Keenan and Niinemets, 2016;Chen et al, 2020), despite observed variations in allometric relationships between leaf functional traits in different conditions such as nutrient and water availabilities (Wright et al, 2001). The consistent slopes suggest that coordinated shifts among parameters are due to fundamental biological trade-offs.…”