Crude oil induces plant growth and antioxidant production in Leersia hexandra Sw. A hydrophytic grass that rhizodegrades oil in Tabasco, Mexico.

Abstract

This study evaluated the survival of the grass Leersia hexandra (Lh) to the stress caused by crude oil (CO), by means of synthesis of reactive oxygen species, antioxidants in leaf-root, and by the rhizospheric bacterial activity of Lh. The experiment was carried out for 180 days, a 4x2 factorial arrangement was applied, four concentrations of CO and two technologies [phytoremediation (PH) with Lh and natural attenuation (NA) with native microorganisms]. The results recorded treatment means with statistical differences (Duncan p ≤ 0.05). Concentrations of 90 g/kg stimulated the formation of young plants (YP) and grass root. In YP leaves, the biosynthesis of H2O2, total phenols (TP) and total flavonoids (TFV) increased due to the effect of CO, as did catalase (CAT) and phenylalanine ammonia lyase (PAL) in roots. Grass roots with low H2O2 synthesis but high synthesis of CAT and PAL are a signal of tolerance to abiotic stress. Rhizosphere of Lh stimulated microbial activity and the population of Azotobacter spp but removal 22% de 90 g/kg the CO, and AN 58%. The results suggest adaptation of Lh to the stress caused by soil contaminated with oil, manifested by regulating the synthesis of H2O2 and antioxidants in leaf-root during the removal of hydrocarbons from oil.