Effects of stomatal density and leaf water content on the ¹⁸O enrichment of leaf water

Abstract

SummaryLeaf water isotopic composition is imprinted in several biomarkers of interest and it is imperative that we understand the isotopic enrichment of leaf water. Here, we test the effect of stomatal density and leaf water content on the oxygen isotopic composition of leaf water in transgenic Arabidopsis plants expressing different stomatal densities, and several other species showing a range of stomatal density.We grew Arabidopsis plants hydroponically and collected other species in the field. Stomatal density and leaf water content were determined for each plant. We measured transpiration and extracted leaf water for isotopic determination. Using these measurements and the current leaf water isotope model, we calculated several of the parameters related to leaf water isotopic enrichment.High stomatal density promoted leaf water isotope enrichment. No conclusion, however, can be drawn regarding the effect of leaf water content on leaf water isotope enrichment. Factors such as transpiration might mask the effect of stomatal density on leaf water isotopic enrichment.We propose a method by which stomatal density can be incorporated in the current Peclet model of leaf water isotope enrichment. These findings have important applications in the use of plant-based metabolic proxies in paleoclimate studies.

Seasonal temperature and precipitation recorded in the intra-annual oxygen isotope pattern of meteoric water and tree-ring cellulose

“…Plant characteristics that are known to affect absolute d 18 O cell values, but do not change seasonally, would not affect the applicability of the equations presented above. Such characteristics include tree species (e.g., Wang et al, 1998), stomatal density (Larcher et al, 2015), and differences in leaf-water enrichment and transpiration among individual trees (e.g., Gessler et al, 2013). Likewise, absolute d 18 O MW values have been shown to vary as a function of geographic parameters such as elevation (altitude) or distance from the coast (e.g., Dotsika et al, 2010;Dutton et al, 2005;Garzione et al, 2000;Gonfiantini et al, 2001;Rozanski et al, 1993), but these too, do not change seasonally.…”

Leaf carbon and oxygen isotopes are coordinated with the leaf economics spectrum in Mediterranean rangeland species

“…The mechanistic link between leaf morphological/anatomical features and effective path length for water movement within leaves (which influences δ 18 O) has been examined by several studies, but remains elusive to date (Kahmen et al, 2008(Kahmen et al, , 2009. Recent studies have shown links between 18 O enrichment of leaf water and leaf traits not included in classical LES studies, such as stomatal or vein density (Holloway-Phillips et al, 2016;Larcher, Hara-Nishimura, & Sternberg, 2015).…”

Selection of Poplar Genotypes for Adapting to Climate Change

“…Leaves growing under water deficit usually develop smaller and more densely distributed stomata [2]. These modifications in morphological characteristics make leaves able to reduce transpiration with a quicker onset of stomatal regulation [51,52]. Thus, most of the clones tested in our study showed adaptive acclimatization to the region of deployment.…”