ANTIOXIDATIVE RESPONSES OF Adesmia subterránea SEEDLINGS EXPOSED TO HEAVY METALS STRESS

PARERA V.,; GALLARDO L.; GATICA CV; PÉREZ CHACA VM; PARERA CA; FERESIN GE

Mendoza

Congreso; XL Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2022

Sociedad de Biologia de Cuyo

A prerequisite to beginning a successful phytoremediation program is the selection of adequate plant species capable to tolerate heavy metal stress. It will depend on the ability to cope with reactive oxygen species (ROS), by triggering the enzymatic and non-enzymatic antioxidant system. Fabaceae species are efficient in different phytoremediation processes. The aim was to evaluate the seedling establishment, the activity of the antioxidant enzymes and parameters of oxidative stress of A. subterránea under conditions of stress due to Cd and Hg. Plants were grown semi hydroponically using vermiculite as substrates in solutions of different Cd (3, 4.5, and 6 ppm) and Hg (0.8, 1.2 and 1.6 ppm) concentrations and a control treatment (distilled water). Three replicates (25 seedlings) per level of treatment were tested in a growth chamber under control environmental conditions (T° 20°C day/night 12hs light/dark). Statistical analysis for enzyme activity was performed using ANOVA followed Tukey-Kramer Multiple Comparisons Test and generalized linear mixed-effects models with a binomial error distribution was used for seedling establishment. Results showed that the seedling establishment was greater than 70% in all the treatments and control Under Hg treatments, the CAT activity (µmol H2O2/mg protein min) decreased as the concentrations increased and was significantly lower compared with the control. While the activity of APX (µmol Ascorbate/mg protein min) and GSH (nMoles GSH/g PF) was similar to the control. Under Cd treatments, the CAT activity and GSH didn´t defer from the control. Contrary, the APX activity was significantly higher in the 4.5 and 6 ppm treatment compared to the control. The application of HM treatments, significant increase in membrane damage (TBARS), but no significant differences were found in the production of extracellular H2O2 with the control. These results suggest that the exposure of A. subterránea to HM induces lipid peroxidation, despite the activation of the enzymatic and non-enzymatic defense. The oxidative stress could be due to another type of ROS rather H2O2. However, this specie managed to establish itself and tolerate different concentrations of heavy metals and could be considered as a potential specie for phytoremediation.