Resumen de Oxygen isotope composition of must‐water in grapevine: effects of water deficit and rootstock
Javier Tardáguila Laso, Massimo Bertamini, F. Reniero, Giuseppe Versini
The influence of soil moisture and different rootstock genotypes on the 18O/16O ratio of must‐water in grapes was investigated. Grapevines (Vitis vinifera L.) with cv. Cabernet Sauvignon as scion grafted on rootstocks 101–14, 420A and 41B were subjected to three levels of plant‐available soil‐water from veraison to harvest. Significant differences were observed in the 18O level of must‐water, the differences being related to water regime and rootstock genotype, with 18O increasing as soil‐water became less available. The higher the canopy‐air vapour pressure gradient (VPG), the larger was the oxygen isotope content of must‐water, indicating that VPG is an important factor in determining the degree of must‐water enrichment under water deficit conditions. In all water regimes of soil, 41B induced the highest degree of 18O enrichment in must‐water. The differences between rootstocks in must‐water 18O could not fully be explained either by the rootstock effect on VPG or on root distribution.
