The slope of assimilation rate against stomatal conductance should not be used as a measure of water use efficiency or stomatal control over assimilation
Chandra Bellasio
Abstract
uptake are pivotal in physiology and efforts to improve crop yields. Although tempting, relying on regression slopes from assimilation-stomatal conductance plots to estimate water use efficiency or stomatal control over assimilation is erroneous. Through numerical simulations, I substantiate this assertion. I propose the term 'instantaneous transpiration efficiency' for the assimilation-to-transpiration ratio to avoid confusion with 'intrinsic water use efficiency' which refers to the assimilation-to-stomatal conductance ratio, and recommend to compute both metrics for each gas exchange data point.
Topics & Concepts
TranspirationStomatal conductanceAssimilation (phonology)Data assimilationWater-use efficiencyConfusionConductanceEnvironmental scienceAgronomyChemistryMathematicsPhotosynthesisBotanyBiologyMeteorologyPhysicsPsychologyPsychoanalysisPhilosophyLinguisticsCombinatoricsPlant Water Relations and Carbon DynamicsGreenhouse Technology and Climate ControlClimate change impacts on agriculture