Conclusions
In conclusion, table grape vines under preconditioning treatments responded by reducing photosynthetic activity,biomass
accumulation and vine growth. After the stress period, the negative effects on water relations and gas exchange parameters
(mainly gs) were compensated for under the recovery period. Vines
exposed to moderate water stress conditions developed avoidance/tolerance mechanisms to drought that were mainly based on
stomatal closure, reduction of leaf insertion angle and defoliation.
Un-preconditioned vines (CTL-2) were not able to compensate for
turgor loss, had growth inhibition and the most severe dehydration
damages together with those observed in PRDFIX. Moreover, the
stomatal behaviour was conditioned to the diurnal basis or the time
of the day when the stress was applied. These findings should be
borne in mind for irrigation scheduling of this cultivar under commercial field conditions due to the hardness that exhibited vines