Productivity, enzymatic activity and physiological effects in peanut plants associated with arbuscular mycorrhizal fungus and supplemented with seaweed extract

Peanuts cultivation (Arachis hypogae L.) has aroused great economic interest. Therefore, use of arbuscular mycorrhizal fungi (FMAs) and natural biostimulants such as soluble seaweed extract (ESA) is spreading in agriculture. These biological agents can stimulate the growth and production of vegetables. The objective of this work was to evaluate the effects on gas exchange, enzymatic activity and production indexes in peanut plants inoculated with mycorrhizal fungi and supplemented with soluble extract of marine algae. The experimental design was completely randomized in a 2x2 factorial scheme, two treatments involving the presence and absence of FMAs and two treatments involving supplementation or not with ESA, T₁ consisted of plants associated to FMAs and supplemented with ESA, T₂, just FMAs associated plants, T₃ plants only supplemented with ESA and T4 control plants (no association with fungi and no supplementation with ESA). The variables evaluated were net assimilation rate of CO₂ (A), stomatal conductance (gs), transpiration (E) and internal carbon concentration (Ci), activities of the antioxidative enzymes sod, pod, cat and proline protective osmolyte as well as yield and yield components. This consortium also increased the distribution of biomass with direct effects on the increase of production. The biological agent and the biostimulant collaborated in the activation and kept active the antioxidative system of the peanut plants even under optimal conditions of cultivation. Management practices that maintain the native community of mycorrhizal fungi, such as ESA application in plants associated to FMAs, would be good biotechnological alternatives for the cultivation of IAC Runner 886 peanuts.