Effect of high CO2 and water availability on whole plant carbon and water balance in grapevine

Abstract

[eng] Water scarcity is one of the main challenges in vineyards sustainability in most of the grapevine áreas, now and even more in near future to due climatic change perspectives. For that reason, water use efficiency measurements are one of the highest interest to improve the sustainability of this crop. Since the vast majority of studies relays on measurements of carbon and water fluxes at the leaf scale, less data are available at the whole-plant scale. For this reason, in this experiment, whole-plant water and carbon fluxes in grapevine exposed to two different water regimes and under high CO2 concentrations were measured, in order to check its effect at the whole-plant scale. The results obtained showed that water and carbon fluxes are well coordinated between themselves under both water treatments. Under drought conditions, both fluxes were reduced, but surprisingly the estimated water use efficiency was decreased, contrarily to what is shown at the leaf scale. Finally, high CO2 measurements indicated an increase of whole-plant NCE as well as increased whole-plant water use efficiency, mainly in non-watered plants.