Humic acids of vermicompost as an ecological pathway to increase resistance of rice seedlings to water stress

Abstract

This paper discussed the potential role of humic acids (HA) in preventing oxidative stress in rice plants submitted to water stress. The rice seedlings (Oryza sativa L. cv. IACUB-30) was grown in nutrient solution and HA were extracted from vermicompost and analysed using Fourier-transform infrared (FTIR) spectroscopic and chemical methods. Changes in plant anatomy and morphology before and after stress initiation were employed as biomarkers of plant response. The growth rate over time, water content, dry-mass content, leaf carbohydrates, protein content and amino-acid content were among the parameters evaluated. Peroxidases (POX) activity, proline content, H₂O₂ content and membrane permeability were also studied. The results show that HA induced POX activity leading to a reduction in H₂O₂ content and greater conservation of membrane permeability. These results indicate that the HA play an important role as ecological and safety alternative to prevent oxidative stress in plant caused by drought stress. Our findings provide novel evidence for the protective action of HA against oxidative stress caused by water deficits.

Key words: Peroxidases, oxidative stress, humic acid.