Mapping ‘hydroscapes’ along the iso- to anisohydric continuum of stomatal regulation of plant water status

Abstract

The concept of iso- vs. anisohydry has been used to describe the stringency of stomatal regulation of plant water potential (ψ). However, metrics that accurately and consistently quantify species’ operating ranges along a continuum of iso- to anisohydry have been elusive. Additionally, most approaches to quantifying iso/anisohydry require labour-intensive measurements during prolonged drought. We evaluated new and previously developed metrics of stringency of stomatal regulation of ψ during soil drying in eight woody species and determined whether easily-determined leaf pressure–volume traits could serve as proxies for their degree of iso- vs. anisohydry. Two metrics of stringency of stomatal control of ψ, (1) a ‘hydroscape’ incorporating the landscape of ψ over which stomata control ψ, and (2) the slope of the daily range of ψ as pre-dawn ψ declined, were strongly correlated with each other and with the leaf osmotic potential at full and zero turgor derived from pressure–volume curves.

Citation

Meinzer, Frederick C.; Woodruff, David R.; Marias, Danielle E.; Smith, Duncan D.; McCulloh, Katherine A.; Howard, Ava R.; Magedman, Alicia L. 2016. Mapping ‘hydroscapes’ along the iso- to anisohydric continuum of stomatal regulation of plant water status. Ecology Letters. 19(11): 1343-1352.