Ecophysiology of peanuts grown under water deficit regimes

Abstract

This study evaluates physiological aspects of two peanut cultivars (Arachis hypogaea L. IAPAR 25 Tição and IAC Tatu ST) grown under water regimes in order to verify drought tolerance. The randomized block experi­mental design was used in a 2 x 3 factorial design (two cultivars and three water regimes). The water regimes were, namely: control, in which plants were maintained at field capacity conditions (FC - without water deficit); moderate water deficit (MD - 50% of water deficit); and severe water deficit (SD - 75% of water deficit) in relation to control. Relative water content, gas exchange, dry matter, and leaf proline content were analyzed. Both cultivars developed physiological mechanisms of acclimatization to water deficit, such as reducing leaf relative water content, CO₂ assimilation rate, stomatal conductance, and transpiration in the initial period of water deficit, besides increasing proline production. Such physiological changes negatively affected dry matter accumulation in the grains and the number of grains, as well as dry matter accumulation in shoots and roots.