Transpiration response to soil drying and vapor pressure deficit is soil texture specific

• Published in: Plant and soil Vol. 500; no. 1-2; pp. 129 - 145
• Main Authors: Cai, Gaochao, König, Maria, Carminati, Andrea, Abdalla, Mohanned, Javaux, Mathieu, Wankmüller, Fabian, Ahmed, Mutez Ali
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.07.2024; Springer; Springer Nature B.V
• Subjects: Agriculture; Analysis; Biomedical and Life Sciences; Canopies; canopy; Conductance; Corn; Drying; Ecology; Fluid flow; fluid mechanics; Growth; hydraulic conductivity; Hydraulics; leaf water potential; Leaves; Life Sciences; Loam; Moisture content; Plant Physiology; Plant Sciences; Plants; Research Article; Sand; Soil conductivity; Soil investigations; soil matric potential; Soil moisture; Soil properties; Soil Science & Conservation; Soil texture; Soil water; soil water deficit; species; Stomata; stomatal movement; Terrestrial ecosystems; Texture; Transpiration; Vapor pressure; vapor pressure deficit; Vapors; Water; Water deficit; Water potential; Water shortages; Zea mays; Switzerland; Germany; Stomatal regulation; Leaf water potential; Maize; VPD; Drought; Canopy conductance; Soil–plant hydraulic conductance
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-022-05818-2

Aims Although soil water deficit is the primary constraint on transpiration globally, the mechanisms by which soil drying and soil properties impact transpiration and stomatal regulation remain elusive. This work aimed to investigate how soil textures and vapor pressure deficit (VPD) impact the relationship between transpiration rate, canopy conductance, and leaf water potential of maize ( Zea mays L.) during soil drying. We hypothesize that the decrease in soil–plant hydraulic conductance ( K sp ) triggers stomatal closure and the latter is soil specific. Methods Plants were grown in two contrasting soil textures (sand and loam) and exposed to two consecutive VPD levels (1.8 and 2.8 kPa). We measured transpiration rate, canopy conductance, soil and leaf water potentials during soil drying. Results Transpiration rate decreased at higher soil matric potential in sand than in loam at both VPD levels. In sand, high VPD generated a steeper drop in canopy conductance with decreasing leaf water potential. The decrease in canopy conductance was well correlated with the drop in K sp , which was significantly affected by soil texture. Conclusions Our results demonstrated that variations in canopy conductance were not simply a function of leaf water potential but largely affected by soil hydraulics. These results reinforce a model of stomatal closure driven by a loss in soil hydraulic conductivity. Further studies will determine if soil-specific stomatal regulation exists among species.