Leaf water potential measurements using the pressure chamber: Synthetic testing of assumptions towards best practices for precision and accuracy. (23rd April 2022)

• Record Type: Journal Article
• Authors: Rodriguez‐Dominguez, Celia M.; Forner, Alicia; Martorell, Sebastia; Choat, Brendan; Lopez, Rosana; Peters, Jennifer M. R.; Pfautsch, Sebastian; Mayr, Stefan; Carins‐Murphy, Madeline R.; McAdam, Scott A. M.; Richardson, Freya; Diaz‐Espejo, Antonio; Hernandez‐Santana, Virginia; Menezes‐Silva, Paulo E.; Torres‐Ruiz, Jose M.; Batz, Timothy A.; Sack, Lawren
• Is Part Of: Plant, cell and environment. Volume 45:Number 7(2022)
• Page Start: 2037
• Page End: 2061
• Publication Date: 2022-04-23
• Subjects: leaf water potential -- plant water relations -- plant water status -- pressure bomb -- pressure chamber -- water stress; Plant physiology -- Periodicals; Plant cells and tissues -- Periodicals; Plant communities -- Periodicals; 581.105
• DOI: 10.1111/pce.14330
• Languages: English
• ISSNs: 0140-7791

Abstract

Abstract: Leaf water potential ( ψ leaf ), typically measured using the pressure chamber, is the most important metric of plant water status, providing high theoretical value and information content for multiple applications in quantifying critical physiological processes including drought responses. Pressure chamber measurements of ψ leaf ( ψ leafPC ) are most typical, yet, the practical complexity of the technique and of the underlying theory has led to ambiguous understanding of the conditions to optimize measurements. Consequently, specific techniques and precautions diversified across the global research community, raising questions of reliability and repeatability. Here, we surveyed specific methods of ψ leafPC from multiple laboratories, and synthesized experiments testing common assumptions and practices in ψ leafPC for diverse species: (i) the need for equilibration of previously transpiring leaves; (ii) leaf storage before measurement; (iii) the equilibration of ψ leaf for leaves on bagged branches of a range of dehydration; (iv) the equilibration of ψ leaf across the lamina for bagged leaves, and the accuracy of measuring leaves with artificially 'elongated petioles'; (v) the need in ψ leaf measurements for bagging leaves and high humidity within the chamber; (vi) the need to avoid liquid water on leaf surfaces; (vii) the use of 'pulse' pressurization versus gradual pressurization; and (viii) variation among experimenters in ψ leafPC determination. Based on our findings we provide a best practice protocol to maximise accuracy, and provide recommendations for ongoing species‐specific tests of important assumptions in future studies. Summary statement: Key assumptions on pressure chamber leaf water potential ( ψ leafPC ) measurements were tested towards recommending best practices. Support to optimize the method was found, enabling concrete suggestions to maximize accuracy, and providing recommendations for species‐specific tests of additional assumptions in future studies.