Defensa química en orquídeas mediada por mecanismos antioxidantes

Abstract

Oxidative stress generated as a consequence of the influence of abiotic factors such as temperature, humidity, salinity, soil type and chemical composition lead to the appearance of reactive oxygen species as an immediate response. The changes experienced by plants during the response induce variations in the concentration and composition of antioxidant molecules and factors as a result of natural physiological processes, making it possible to establish a direct relationship between the loss of plant material and an imbalance during the defense. Chemical defense mediated by antioxidant production can be approximated by spectrophotometric assays. The present project evaluated the antioxidant response of the orchid Epidendrum secundum Jacq; grown under in vitro and in vivo conditions. ABTS and DPPH free radical scavenging was evaluated, and phenolic compounds were quantified by the Folin-Ciocalteau method. The enzymatic activity against catalase and peroxidase was evaluated by spectrophotometric assays. The results indicate a significantly higher antioxidant activity and production of phenolic compounds in the plant grown in vivo, suggesting that external environmental conditions lead to the production of non-enzymatic antioxidants. For enzymatic evaluation, the results demonstrate that culture conditions influence specific enzyme activation, showing significant variability in catalase and peroxidase response in response to stress. This indicates that tissues developed both in vitro and in vivo activate specific enzymatic defense strategies in response to these environmental and laboratory culture conditions.