S20 - Session P3 - Water stress physiological response and aquaporin expression in own-rooted grapevine plants and wine grape rootstock/scion combinations (Vitis spp)

Authors: Andrea Galaz, Alonso Perez-Donoso, Marina Gambardella *

The water shortage affects main wine producers' areas worldwide, and being of great relevance to know the physiological and molecular mechanisms that occur during periods of drought. Based on stomatal behavior, two strategies have been described adopted by Vitis plants to regulate water under conditions of water stress: isohydric and anisohydric behaviors. However, according to bibliographic background, this classification for various genotypes is not clear yet and there is not enough information about the effect that the rootstock has on the general behavior of the plant. In this context, two trials were carried out: in the first, 4 own-rooted genotypes of the genus Vitis spp , two rootstocks (1103P considered drought tolerant and SO4 poorly tolerant) and two cultivars (cv Cabernet and cv Carmenere) were evaluated. The plants were subjected to water stress for periods of 7 and 14 days and then to recovery periods. Stem water potential, stomatal conductance and growth rate were evaluated. A behavior close to anisohydric was observed in all the genotypes studied. In the second trial, three graft / rootstock combinations were studied: cv. C. Sauvignon grafted onto itself, onto 1103P and onto 101-14. Although no differences were observed at the level of stomatal conductance and water potential, in the recovery period there were significant differences in the expression levels of the aquaporins VvPIP2; 1, VvPIP2; 2, VvTIP1; 1, VvTIP2; 1. Cabernet Sauvignon plants grafted on 1103P and 101-14 showed a higher level of expression. That is, the combinations with rootstocks of different genetic origin responded better to the irrigation suspension treatment and recovered faster, indicating a beneficial effect of the interaction of genotypes in this type of responses.