Gas exchanges in Vitis vinifera under water stress regime. I. Characterization of the variety behavior

Abstract

The effects of the application of water stress on the gas exchanges of cultivars of grapevine (Vitis vinifera L.), through measurements of the photosynthesis and stomatal conductances in isolated leaves and the entire plant, were analysed with the purpose of characterizing the behavior of different cultivars. Plants of 1 to 2 years old, grafted on 'Fercal', potted and cultivated in a green house and phytotron were used. The gas exchanges were measured with infrared CO 2 analysers, one being portable (ADC-LCA3) for the isolated leaves, and a Double Assimilation and Transpiration Chamber (CAT) for the entire plant. The evolution of the water stress greatly reduced the photosynthesis and stomatal conductances of the leaves, revealing different sensitivity levels between the cultivars. Two groups were distinguished: a sensitive one, with greater reductions in the carbon assimilation rates, formed by the cultivars S6millon and Ugni blanc; and the other one, more adapted, represented by the cultivars Alexandria Moschatel, Chardonnay and Arriloba.