Modelling water use efficiency in a dynamic environment: An example using Arabidopsis thaliana. (October 2016)

• Record Type: Journal Article
• Authors: Vialet-Chabrand, S.; Matthews, J.S.A.; Brendel, O.; Blatt, M.R.; Wang, Y.; Hills, A.; Griffiths, H.; Rogers, S.; Lawson, T.
• Is Part Of: Plant science. Volume 251(2016:Oct.)
• Page Start: 65
• Page End: 74
• Publication Date: 2016-10
• Subjects: Stomatal conductance -- Photosynthesis -- Dynamics -- Diurnal -- Intrinsic water use efficiency; Botany -- Periodicals; Botanique -- Périodiques; 580
• DOI: 10.1016/j.plantsci.2016.06.016
• Languages: English
• ISSNs: 0168-9452

Abstract

Highlights: A model scaling stoma behaviour at leaf level is proposed. The model is tested by reproducing natural variations of light intensity. Stomatal aperture and photosynthesis decrease as a function of sugar accumulation. Leaf anatomy influences the rapidity of stomatal conductance. The model dissects intrinsic water use efficiency into traits of interest. Abstract: Intrinsic water use efficiency ( Wi ), the ratio of net CO2 assimilation ( A ) over stomatal conductance to water vapour ( gs ), is a complex trait used to assess plant performance. Improving Wi could lead in theory to higher productivity or reduced water usage by the plant, but the physiological traits for improvement and their combined effects on Wi have not been clearly identified. Under fluctuating light intensity, the temporal response of gs is an order of magnitude slower than A, which results in rapid variations in Wi . Compared to traditional approaches, our new model scales stoma behaviour at the leaf level to predict gs and A during a diurnal period, reproducing natural fluctuations of light intensity, in order to dissect Wi into traits of interest. The results confirmed the importance of stomatal density and photosynthetic capacity on Wi but also revealed the importance of incomplete stomatal closure under dark conditions as well as stomatal sensitivity to light intensity. The observed continuous decrease of A and gs over the diurnal period was successfully described by negative feedback of the accumulation of photosynthetic products. Investigation into the impact of leaf anatomy on temporal responses of A, gs and Wi revealed that a high density of stomata produces the most rapid response of gs but may result in lower Wi .