Influence of genotype and water availability on respiratory costs and plant carbon balance in grapevines (Vitis vinifera L.)

Abstract

Due to the important contribution of agriculture to the global carbon dioxide (CO₂) balance, new techniques are currently being developed to accurately estimate the carbon balance of different crops. Field studies to date in grapevines have been based on carbon allocation and biomass accumulation dynamics. Such field studies show the carbon balances, but the respiratory losses and their changes along the vegetative cycle under different soil water availability are poorly considered or absent because of the paucity of information about them. In order to study the effect of cultivar and irrigation on respiratory losses and plant carbon balance, a field experiment was carried out during 2013 and 2014 seasons using the cultivars Grenache and Tempranillo and two treatments: irrigation and non-irrigation. The CO₂ exchange and biomass of leaves, stems, roots and clusters were measured throughout the vegetative cycle. The results showed integrated carbon respiratory losses for leaves, fruits and roots along the vegetative cycle in irrigated and non-irrigated plants. Carbon respiration losses where higher for irrigated plants while the percentage of carbon loss respect to the total fixed carbon were higher in non-irrigated plants. An important, and significant genotype effect was present. Tempranillo showed the highest values in carbon fixation, leaf and stem respiration, as well as the highest values in aerial biomass. However, higher values of root respiration losses were observed in Grenache, and was the cultivar that located higher values of biomass of the perennial organs.