The coupled fluxes of carbon dioxide (CO2) and water between leaves and atmosphere are strongly regulated by the opening and closure an especial group of cells (i.e. stomata), and by water supplied through the xylem. The first plant response under water scarcity is stomatal closing which avoids the loss of water through transpiration, limiting photosynthesis in the process. This trade-off has immediate implications for plant and fruit growth. A better comprehension of this constriction is needed to understand regulation of the whole-plant water and carbon fluxes (from leaves to fruits) under drought stress. The overarching goal of this project is to provide a better understanding of this regulation through the study of the plant water and sugar fluxes. An
integrated mechanistic model of water and sugar transport will be developed to unravel the main components of carbon assimilation and water losses, and its implications for plant growth and fruit development. For this purpose we chose the grapevine (Vitis vinifera L.) as model plant, because of its unique characteristics to cope with drought and its relevance in agriculture around the world. For these goals, we will use plants under greenhouse-controlled conditions and a commercial Mediterranean vineyard in Spain. Therefore, with this integrative approach we expect to better understand the ways of regulating water and carbon fluxes in plants and also to find improved ways for water management in agriculture and horticulture.