Impact of stomatal density on the hydraulic properties of Arabidopsis thaliana: Studies on transpiration rate and hydraulic conductivity of the root

PABLO CÁCERES; MOIRA SUTKA; MILAGROS SAMPAOLESI; TOMÁS FIORINI; GABRIELA AMODEO; IRENE BAROLI

Rosario

Congreso; XXXIV Reunión Argentina de Fisiología vegetal; 2023

Plants have the ability to maintain optimal water status in response to environmental changes, tolerating stress conditions by modifying their hydraulic parameters. Among the main adjustment mechanisms are the regulation of stomatal opening and closure, as well as water conduction properties in plant tissues. Particularly, the efficiency of water transport at the cellular level is influenced by membrane permeability, which is regulated by intrinsic facilitating proteins known as aquaporins. In this study, we investigated the relationship between hydraulic properties of roots and rosettes in lines of Arabidopsis thaliana with mutations in the EPF1 and EPF2 genes, resulting in a 2.5-fold increased stomatal density and a higher transpiration rate. We investigated whether the higher transpiration rates correlated with the plant´s hydraulic properties. For this purpose, we used hydroponic cultivation to preserve the root system completely intact. Although we observed 23% increases on transpiration rates in the epf1 epf2 double mutants plants, we found no significant changes on root hydraulic conductivity, aquaporin contribution to root water transport, root and leaf osmotic potential, or leaf relative water content. Additionally, we present the analysis comparing the expression profile of water-transporting specialized aquaporins between mutant and wild-type plants. These findings suggest that Arabidopsis plants grown under favorable conditions have the ability to maintain similar root hydraulic conductivity, even when faced with a significant increase in transpiration rate. These findings contribute to our understanding of hydraulic regulation mechanisms in plants and their adaptation to different environmental conditions.