Sensitivity of olive leaf turgor to air vapour pressure deficit correlates with diurnal maximum stomatal conductance
- Author(s): Rodriguez-Dominguez, CM
- Hernandez-Santana, V
- Buckley, TN
- Fernández, JE
- Diaz-Espejo, A
- et al.
Published Web Locationhttps://doi.org/10.1016/j.agrformet.2019.04.006
© 2019 The Authors Effective study and management of crops and forests would benefit greatly from useful plant-based indicators of the biological controls on evapotranspiration, and particularly stomatal conductance (g s ). Given the strong influence of g s on bulk leaf water potential and turgor pressure (P), in vivo measurement of P may provide useful information about diurnal or seasonal dynamics of g s . Moderate plant water stress affects the diurnal dynamics of P as leaf-to-air vapour pressure deficit (D) varies, and these dynamics correlate to g s . Here, we explored relative changes in P in response to changes in D under mild drought conditions, and how these changes are linked to stomatal behaviour, and specifically to diurnal maximum g s (g s,max ), one of the best indicators of plant water stress. We monitored ecophysiological and environmental variables, as well as a relative proxy for P, during three consecutive seasons in a hedgerow olive orchard where trees were supplied with different irrigation treatments to create well-watered and moderately water-stressed conditions. Our results demonstrated that the sensitivity of P to D correlated well with g s,max reached by the trees within a range in which variations in g s are the main diffusional limitation to photosynthesis. We further showed that this correlation held under a wide range of meteorological conditions and soil water availability. This turgor proxy measurement, which is much easier to measure than g s , can facilitate the use of g s,max as an indicator of plant water stress and evapotranspiration in agriculture and plant science research.
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