Physiological parameters and protective energy dissipation mechanisms expressed in the leaves of two Vitis vinifera L. genotypes under multiple summer stresses

摘要: Photosynthetic performances and energy dissipation mechanisms were evaluated on the anisohydric cv. Sangiovese isohydric Montepulciano (Vitis vinifera L.) under conditions of multiple summer stresses. Potted vines both cultivars maintained at 90% 40% maximum water availability from fruit-set to veraison. One week before veraison, predawn midday, main gas-exchange chlorophyll fluorescence parameters, content, xanthophyll pool cycle catalase activity evaluated. Under deficit elevated irradiance temperature, contrary despite a significant leaf potential decrease, Sangiovese's leaves kept their stomata more open continued assimilate CO2 while also showing higher use efficiency. these environmental conditions, in comparison with Montepulciano, protective exerted by were: (i) stomatal conductance thermoregulation linked transpiration rate; (ii) greater ability dissipating efficiently excess via xanthophylls (thermal dissipation) due VAZ increase de-epoxidation activity.