Functional coordination between leaf gas exchange and vulnerability to xylem cavitation in temperate forest trees

Abstract

We examined functional coordination among stem and root vulnerability to xylem cavitation, plant water transport characteristics and leaf traits in 14 co-occurring temperate tree species. Relationships were evaluated using both traditional cross-species correlations and phylogenetically independent contrast (PIC) correlations. For stems, the xylem tension at which 50% of hydraulic conductivity was lost ( Ψ Ψ Ψ Ψ 50 ) was positively associated ( P < < < < 0.001) with specific conductivity ( K S ) and with mean hydraulically weighted xylem conduit diameter ( D h-w ), but was only marginally ( P = = = = 0.06) associated with leaf specific conductivity ( K L ). The PIC correlation for each of these relationships, however, was not statistically significant. There was also no relationship between root Ψ Ψ Ψ Ψ 50 and root K S in either crossspecies or PIC analysis. Photosynthetic rate ( A ) and stomatal conductance ( g s ) were strongly and positively correlated with root Ψ Ψ Ψ Ψ 50 in the cross-species analysis ( P < < < < 0.001), a relationship that was robust to phylogenetic correction ( P < < < < 0.01). A and g s were also positively correlated with stem Ψ Ψ Ψ Ψ 50 in the cross-species analysis ( P = = = = 0.02 and 0.10, respectively). However, only A was associated with stem Ψ Ψ Ψ Ψ 50 in the PIC analysis ( P = = = = 0.04). Although the relationship between vulnerability to cavitation and xylem conductivity traits within specific organs (i.e. stems and roots) was weak, the strong correlation between g s and root Ψ Ψ Ψ Ψ 50 across species suggests that there is a trade-off between vulnerability to cavitation and water transport capacity at the whole-plant level. Our results were therefore consistent with the expectation of coordination between vulnerability to xylem cavitation and the regulation of stomatal conductance, and highlight the potential physiological and evolutionary significance of root hydraulic properties in controlling interspecific variation in leaf function.

Changes in Community-Level Riparian Plant Traits over Inundation Gradients, Colorado River, Grand Canyon

“…In contrast, weak correlation between SLA and seed mass in both years (r s = 0.04, r s = 0.11) is consistent with the hypothesis that these traits are distinct axes of trait variation, with SLA representing leaf investment and physiology, and seed mass representing reproductive strategy. Moderate correlations between SLA and SSG (r s = −0.48 in 2013, r s = −0.27 in 2014) suggests a general co-occurrence of low-density, hydraulically efficient stems with thin, high-gas-exchange leaves consistent with other studies (Bucci et al 2004;Maherali et al 2006;Ishida et al 2008). This coordination is also a likely driver for the moderate correlation of SSG and height (r s = −0.51 in 2013, r s = −0.50 in 2014), with greater community-level height and canopy size requiring greater support and carbon investment in stem tissue.…”

The Hydraulic Architecture of Populus

“…LSC for fi eld-grown hybrid poplar and aspen trees was well within range of values reported for Acer and Quercus species (Woodrum et al 2003 ;Maherali et al 2006 ;Bhaskar et al 2007 ). Hybrid poplar clones tended to have higher leaf-specifi c conductivities than aspen genotypes, consistent with a tendency for higher leaf-toxylem area ratios and more negative leaf water potentials in aspen compared with hybrid poplars (Schreiber et al 2011 ).…”

Weak coordination among petiole, leaf, vein, and gas‐exchange traits across Australian angiosperm species and its possible implications

“…Yet, it is equally important to understand why coordination among these traits is often weak or absent across species, as reported here and elsewhere (angiosperms in Brodribb and Holbrook 2006; Maherali et al. 2006; angiosperms in Brodribb et al. 2007; Fichot et al.…”