Canopy height and climate dryness parsimoniously explain spatial variation of unstressed stomatal conductance

Abstract

The spatio-temporal variation of stomatal conductance directly regulates photosynthesis, water partitioning, and biosphereatmosphere interactions. While many studies have focused on stomatal response to stresses, the spatial variation of unstressed stomatal conductance remains poorly determined, and is usually characterized in land surface models (LSMs) simply based on plant functional type (PFT). Here, we derived unstressed stomatal conductance at the ecosystem-scale using observations from 115 global FLUXNET sites. When aggregated by PFTs, the across-PFT pattern was highly consistent with the parameterizations of LSMs. However, PFTs alone captured only 17\% of the variation in unstressed stomatal conductance across sites. Within the same PFT, unstressed stomatal conductance was negatively related to climate dryness and canopy height, which explained 45\% of the total spatial variation. Our results highlight the importance of plant-environment interactions in shaping stomatal traits. The trait-environment relationship established here provides an empirical approach for improved parameterizations of stomatal conductance in LSMs.

Global net biome CO2exchange predicted comparably well using parameter–environment relationships and plant functional types

“…The top-down EF-based hypotheses implemented here yielded NBE errors that matched or outperformed those from traditional PFTs at a sizable fraction of pixels (55%; Figure 4d), suggesting that the introduction of more realistic trait variability in large-scale TBMs can help to improve predictions of its future behavior, as previously hypothesized (Matheny et al, 2017;Scheiter et al, 2013;van Bodegom et al, 2014;Xu & Trugman, 2021). Overall, our findings support the growing paradigm shift away from the representation of static PFTs and towards the incorporation of realistic trait variability into large-scale TBMs (Berzaghi et al, 2020;Bloom et al, 2016;Jung & Hararuk, 2022;Liu et al, 2022;van Bodegom et al, 2014). EF-based hypotheses represent one promising and flexible approach for doing so, although they are not a panacea-PFT-based assumptions are still superior at nearly half of vegetated pixels in our analysis (45%; Figure 4d).…”

Canopy Height and Climate Dryness Parsimoniously Explain Spatial Variation of Unstressed Stomatal Conductance

“…Leaf area index was extracted from the MODIS product (MCD15A3H.006, https://doi.org/10.5067/MODIS/MCD15A3H.006). Processed data and source code are available at https://doi.org/10.5281/zenodo.6787779 (Y. Liu, 2022).…”

Genetic and evolutionary dissection of melatonin response signaling facilitates the regulation of plant growth and stress responses

“…193 Stomatal conductance directly regulates photosynthesis, water partitioning, and then improves plant drought tolerance. 278 Stomatal behavior is regulated by various factors. Phytohormones, as endogenous organic substances, play a major role in regulating stomatal conductance.…”

“…AtWRKY54 and AtWRKY70 induced Arabidopsis resistance to salt stress due to improved water retention and stomatal closure 193 . Stomatal conductance directly regulates photosynthesis, water partitioning, and then improves plant drought tolerance 278 . Stomatal behavior is regulated by various factors.…”