Cuticular conductance of adaxial and abaxial leaf surfaces and its relation to minimum leaf surface conductance. Issue 1 (23rd July 2021)

• Record Type: Journal Article
• Authors: Márquez, Diego A.; Stuart‐Williams, Hilary; Farquhar, Graham D.; Busch, Florian A.
• Is Part Of: New phytologist. Volume 233:Issue 1(2022)
• Page Start: 156
• Page End: 168
• Publication Date: 2021-07-23
• Subjects: abaxial cuticular conductance -- adaxial cuticular conductance -- amphistomatous leaf -- cuticular conductance to water -- leaf gas exchange -- nocturnal conductance -- photosynthetic induction; Botany -- Periodicals; 580
• DOI: 10.1111/nph.17588
• Languages: English
• ISSNs: 0028-646X

Abstract

Summary: Cuticular conductance to water ( g cw ) is difficult to quantify for stomatous surfaces due to the complexity of separating cuticular and stomatal transpiration, and additional complications arise for determining adaxial and abaxial g cw . This has led to the neglect of g cw as a separate parameter in most common gas exchange measurements. Here, we describe a simple technique to simultaneously estimate adaxial and abaxial values of g cw, tested in two amphistomatous plant species. What we term the 'Red‐Light method' is used to estimate g cw from gas exchange measurements and a known CO2 concentration inside the leaf during photosynthetic induction under red light. We provide an easy‐to‐use web application to assist with the calculation of g cw . While adaxial and abaxial g cw varies significantly between leaves of the same species we found that the ratio of adaxial/abaxial g cw (γn ) is stable within a plant species. This has implications for use of generic values of g cw when analysing gas exchange data. The Red‐Light method can be used to estimate total cuticular conductance ( g cw‐T ) accurately with the most common setup of gas exchange instruments, i.e. a chamber mixing the adaxial and abaxial gases, allowing for a wide application of this technique. Abstract : See also the Commentary on this article by Cernusak & De Kauwe, 233 : 5–7 .