Rootstock control of scion response to water stress in grapevine

- Different combinations of rootstock and scion of Vitis genotypes were tested.
- Cell-to-cell water pathway were genotype-related on both root and leaf tissues.
- Rootstock genotype differences in water extraction were maintained on excised roots.
- Cultivar differences in stomatal conductance were maintained on excised leaves.

Rootstocks play a major role in grapevine tolerance to water stress by controlling and adjusting the water supply to shoot transpiration demand. This study aimed to characterize the influence of rootstock genotypes in the adaptive response of scions to water limiting conditions. The effect of rootstock genotype (140Ru and SO4) was observed in the different availability of water provided to the scions (Cabernet Sauvignon, Grenache, Merlot, Syrah), while scions influenced stomatal control of water transpiration. Implication on the cell-to-cell component of plant water transport in both rootstock and scion impacted on embolisms formation in roots and on hydraulics of leaves. The main conclusion of the present study was that rootstock and scion genotypes are able to confer to the plant traits of drought adaptability influencing respectively the capacity of water extraction from the soil and the sensitivity of the stomatal control.