The blind men and the elephant: the impact of context and scale in evaluating conflicts between plant hydraulic safety and efficiency

Abstract

Given the fundamental importance of xylem safety and efficiency for plant survival and fitness, it is not surprising that these are among the most commonly studied features of hydraulic architecture. However, much remains to be learned about the nature and universality of conflicts between hydraulic safety and efficiency. Although selection for suites of hydraulic traits that confer adequate plant fitness under given conditions is likely to occur at the organismal level, most studies of hydraulic architecture have been confined to scales smaller than the whole plant, such as small-diameter branches and roots. Here we discuss the impact of the spatial and temporal contexts in which hydraulic traits are studied on the interpretation of their role in maintaining plant hydraulic function. We argue that further advances in understanding the ecological implications of different suites of plant hydraulic traits will be enhanced by adopting an integrated approach that considers variation in hydraulic traits throughout the entire plant, dynamic behavior of water transport, xylem tension and water transport efficiency in intact plants, alternate mechanisms that modulate hydraulic safety and efficiency, and alternate measures of hydraulic safety and safety margins.

Wood Anatomy and Plant Hydraulics in a Changing Climate

“…These hydraulic trade-offs are components of overall species strategies for acquisition of other resources in addition to water (Reich 2014). The classic hydraulic trade-off is one of xylem safety versus efficiency, wherein more conductive xylem is less resistant to drought-induced embolism (Meinzer et al 2010;Sperry et al 2008;Tyree et al 1994). As explained above, capacitance can play a central role in avoidance of tension-induced embolism under nonextreme diurnal conditions.…”

Lignin in Woody Plants under Water Stress: A Review

“…Evolution of xylem structure and architecture has been extensively examined from both functional and ecological perspectives (Bhaskar et al, 2007;Meinzer et al, 2010;Sperry et al, 2008). However, little advance has been achieved on the role of cell wall chemistry and in special lignin content and composition in how xylem traits or how xylem evolution affected the deposition and composition of lignin (Boyce et al, 2004).…”

Nutrient-Induced Modifications of Wood Anatomical Traits of Alchornea lojaensis (Euphorbiaceae)

“…Changes in vessel diameter size generally provide inferences about the potential radial growth rates of trees, since larger vessels have a higher k theo s and consequently ensure increased water supply to support enhanced transpiration and photosynthetic rates (e.g., Meinzer et al, 2008Meinzer et al, , 2010Smith et al, 2013;Hoeber et al, 2014;Oladi et al, 2014). The relation between higher growth capacity and vessel size becomes understandable, considering that the theo.…”