Osmotic potential at full turgor: an easily measurable trait to help breeders select for drought tolerance in wheat

Abstract

This study investigated the relationship between osmotic potential at full hydration (p 100 ) and turgor loss point (Ψ TLP ) in wheat (Triticum aestivum) to determine the potential of using p 100 to predict Ψ TLP under well-watered (WW) and drought (WS) conditions. Two methods for determining p 100 were tested: pressure-volume (PV) analysis and freezing point osmometry. The study also measured p 100 in a range of 38 field-grown wheat cultivars to determine whether there is genetic variation in p 100 under field conditions. p 100 correlated with Ψ TLP using both methods under both water treatments, particularly WS. Genetic variation of p 100 in the field, under rainfed conditions, was greater than controlled conditions and ranged from À0.94 to À1.95 MPa. Overall, the evidence supports development of p 100 as a novel tool for plant breeders to screen large populations of wheat and identify genotypes with lower Ψ TLP , an integrative trait that is related to drought tolerance.

Grassland plants show no relationship between leaf drought tolerance and soil moisture affinity, but rapidly adjust to changes in soil moisture

“…The close relationship between π o‐osm and π tlp means that cell wall elasticity (represented by the modulus of elasticity, ε) does not play an important role in the maintenance of turgor in these grassland species. Our results are in line with previous studies reporting a relationship between π o and π tlp using the pressure–volume curve (Bartlett, Scoffoni, & Sack, , and references therein; Farrell et al, ; Krasser & Kalapos, ; Meinzer et al, ; Mitchell et al, ) and more recently using π o‐osm for tropical and chaparral woody species (Bartlett, Scoffoni, Ardy et al, ; Maréchaux et al, ) and for wheat cultivars (Mart, Veneklaas, & Bramley, ).…”

Dry‐season decline in tree sapflux is correlated with leaf turgor loss point in a tropical rainforest

“…Such linkages between rapidly measured traits and whole‐plant performance are a fundamental requirement of trait‐based plant functional ecology that has remained challenging (Shipley et al, ), particularly so for water use and drought tolerance traits, given the multiple mechanisms underlying these processes (Sack et al, ). We therefore suggest that the measurement of π tlp is informative of the responses of plant water use, and hence potentially growth and whole‐plant performance, during dry seasons (Mart, Veneklaas, & Bramley, ). Some of the trees shed their leaves, in species already known to be semi‐deciduous (Loubry, ).…”

“…We therefore suggest that the measurement of π tlp is informative of the responses of plant water use, and hence potentially growth and whole-plant performance, during dry seasons (Mart, Veneklaas, & Bramley, 2016). Some of the trees shed their leaves, in species already known to be semi-deciduous (Loubry, 1994).…”

Turgor maintenance by osmotic adjustment, an adaptive mechanism for coping with plant water deficits

“…Recently, Mart e t al . () have described an easily measurable technique for estimating osmotic adjustment by measuring the water potential when plants are visibly and permanently wilted (turgor loss point). The degree of osmotic adjustment measured as the water potential at the turgor loss point was correlated with the degree of osmotic adjustment measured by traditional methods and varied among wheat cultivars.…”