Loss of conductance between mesophyll symplasm and intercellular air spaces explains nonstomatal control of transpiration.

ABSTRACT: The conventional assumption is that stomatal conductance ([Formula: see text]) dominates the regulation of water and carbon dioxide fluxes between leaves and the atmosphere. Here, a nanoreporter of water status at the mesophyll cell surface and local xylem within intact maize leaves documents significant undersaturation of water vapor in the outside-xylem zone (OXZ) and a large loss of conductance of this zone ([Formula: see text]) at moderate xylem water stress, without stomatal closure or turgor loss. The ratio of the resistances [Formula: see text] serves as a predictive phenotype of undersaturation, nonstomatal regulation of transpiration, errors in standard gas exchange analysis, and an increase of intrinsic water use efficiency ([Formula: see text]). Cell-scale access to water status

SUBMITTER: Jain P 

PROVIDER: S-EPMC12663939 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature