Early water stress detection on olive trees (Olea europaea L. cvs ‘chemlali’ and ‘Chetoui’) using the leaf patch clamp pressure probe

Abstract Plant water relations and their dependence on microclimate and soil moisture were studied during 45 days in young olive trees cvs Chemlali and Chetoui subjected to a drying period and rehydration. The recently developed leaf patch clamp pressure (LPCP) probe were used for monitoring turgor-dependent leaf patch pressures ( P p) and compared with some conventional methods to detect water stress. Results show that, in well-watered olive plants, diurnal Pp is highly linearly correlated with vapour pressure deficit (VPD). Pp night readings gradually increased with increasing soil drought and revealed the beginning of water stress. At the end of the drying period, when the soil water content reach values less than the wilting point, only Pp curves detect the water stress in the two olive cultivars before the others methods tested here (ex: relative water content, chlorophyll content, chlorophyll fluorescence and stomatal conductance). Non-destructive, continuous leaf turgor pressure method showed promising potential for monitoring and detecting early water stress of young olive tree, in spite of sensibility to water stress, technological and data interpretation challenges requiring further attention.