The determinants of leaf turgor loss point and prediction of drought tolerance of species and biomes: a global meta‐analysis

Abstract

Increasing drought is one of the most critical challenges facing species and ecosystems worldwide, and improved theory and practices are needed for quantification of species tolerances. Leaf water potential at turgor loss, or wilting (π(tlp) ), is classically recognised as a major physiological determinant of plant water stress response. However, the cellular basis of π(tlp) and its importance for predicting ecological drought tolerance have been controversial. A meta-analysis of 317 species from 72 studies showed that π(tlp) was strongly correlated with water availability within and across biomes, indicating power for anticipating drought responses. We derived new equations giving both π(tlp) and relative water content at turgor loss point (RWC(tlp) ) as explicit functions of osmotic potential at full turgor (π(o) ) and bulk modulus of elasticity (ε). Sensitivity analyses and meta-analyses showed that π(o) is the major driver of π(tlp) . In contrast, ε plays no direct role in driving drought tolerance within or across species, but sclerophylly and elastic adjustments act to maintain RWC(tlp,) preventing cell dehydration, and additionally protect against nutrient, mechanical and herbivory stresses independent of drought tolerance. These findings clarify biogeographic trends and the underlying basis of drought tolerance parameters with applications in comparative assessments of species and ecosystems worldwide.

Going Back to Basics: Importance of Ecophysiology when Choosing Functional Traits for Studying Communities and Ecosystems

“…Therefore, a deep ecophysiological understanding is essential to identify more responsive traits to a given environmental driver (Rosado & de Mattos 2010;Bartlett et al 2012;Dias et al 2013b). Studies on community assembly and ecosystem functioning are often using ecophysiological traits as descriptors, but hot topics (e.g.…”

“…Additionally, the importance of traits related to the venation network of leaves, that mediate water and carbon flows in leaves due to routes of distribution of resources, are important underlying traits mediating the relationships between traits in the leaf economic spectrum (Blonder et al 2010). In this sense, even with similar LMA, species might differ in terms of carbon assimilation, leaf longevity and drought tolerance due to differences in the venation network and leaf turgor loss point (Blonder et al 2010;Bartlett et al 2012).…”

“…climate changes, resource availability, disturbances) and ii) the relevant physiological processes allowing species to cope with them, iii) the selection of traits that are involved in such physiological processes and iv) the validation of the selected traits at the community and v) ecosystem scales. global analysis, leaf turgor loss point and osmotic pressure were recently shown to be key traits describing drought tolerance between biomes, instead of LMA (Bartlett et al 2012). Additionally, the importance of traits related to the venation network of leaves, that mediate water and carbon flows in leaves due to routes of distribution of resources, are important underlying traits mediating the relationships between traits in the leaf economic spectrum (Blonder et al 2010).…”

Functional traits associated with plant colonizing and competitive ability influence species abundance during secondary succession: Evidence from subalpine meadows of the Qinghai–Tibetan Plateau

“…It should be noted that, given the generally low annual precipitation at the study site, moisture limitation may be expected to be of importance; thereby, affecting species abundance over succession (Bartlett et al., 2012). However, there were no observed significant changes in leaf turgor loss point–species abundance relationships along the successional gradient.…”

“…The low annual precipitation (<600 mm) and the extremely low temperature in the growing season may force colonist to have high drought and cold stress resistance for colonization. The leaf proline content and turgor loss point are direct measures of plant tolerance/resistance to abiotic stresses (Bartlett, Scoffoni, & Sack, 2012; Krasensky & Jonak, 2012); therefore, it is pertinent for testing the effects of drought and cold stress resistance on species abundance. In addition, the dispersal time (winter) and nitrogen competition in late succession may force species to have different germination strategies (Liu et al., 2013; Zhang et al., 2015).…”