Gas exchange, photochemical efficiency and photosynthetic pigments of peanut cultivars under water deficit in the soil

The peanut is a legume identified as profitable alternative for small producers in the Brazilian semiarid region. In this region, the cultures are often submitted to water deficiency, which is considered a major cause of reduced productivity. The objective of this study was to evaluate the gas exchange, photochemical efficiency, photosynthetic pigments and production of dry biomass of peanut cultivars submitted to different water availability in the soil. The experiment was conducted in a greenhouse in a completely randomized design with factorial arrangement 2 x 3 and six replications. The cultivars were BR1 and BRS Havana, and water treatments were daily water availability, every five days and water availability suspension. The water availability every five days negatively affects gas exchange BRS Havana and the suspension of soil water availability stimulates stomatal closure of two cultivars, reducing stomatal conductance and leaf transpiration, nonetheless considered as an adaptation strategy to this condition. The content of photosynthetic pigments of BR1 and BRS Havana cultivars is reduced with the reduction of water availability in the soil hindering the production of dry biomass. The cultivar BR1 has greater assimilative capacity of CO2 and more efficient use of water.