The selection of adequate agricultural cultural practices and efficient cultivars plays an important role in optimising natural resources. In the present study, the drivers and responses of transpiration in two well-known apple varieties, Golden and Braeburn, were characterised using a combination of methods: stem water potential (ΨStem), sap flow sensors, and stomatal conductance (gs). Golden variety trees were found to have significantly higher leaf area (10.4 m2 vs. 8.1 m2), lower transpiration plasticity in response to water stress, maximal stomatal conductance at a lower vapour pressure deficit (1.29 vs. 1.47 kPa), and warmer sunlit leaves relative to the environment (ΔT, 0.8°C). No effect of variety was found when evaluating the effect of midday ΨStem in gs and ΔT.
