ANTIOXIDATIVE RESPONSES OF Adesmia subterránea SEEDLINGS EXPOSED TO HEAVY METALS STRESS

V PARERA; LV GALLARDO; CV GATICA AGUILAR; MV PEREZ CHACA

Mendoza

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

Sociedad de Biología de Cuyo

A prerequisite to beginning a successful phytoremediation program is theselection of adequate plant species capable to tolerate heavy metal stress. Itwill depend on the ability to cope with reactive oxygen species (ROS), bytriggering the enzymatic and non-enzymatic antioxidant system. Fabaceae speciesare efficient in different phytoremediation processes. The aim was to evaluatethe seedling establishment, the activity of the antioxidant enzymes andparameters of oxidative stress.of A. subterránea under conditions ofstress due to Cd and Hg. Plants were grown semi hydroponically usingvermiculite as substrates in solutions of different Cd (3, 4.5, and 6 ppm) andHg (0.8, 1.2 and 1.6 ppm) concentrations and a control treatment (distilledwater). Three replicates (25 seedlings) per level of treatment were tested in agrowth chamber under control environmental conditions (T° 20°C day/night 12hslight/dark). Statistical analysis for enzyme activity was performed using ANOVAfollowed Tukey-Kramer Multiple Comparisons Test and generalized linearmixed-effects models with a binomial error distribution was used for seedlingestablishment. Results showed that the seedling establishment was greater than70% in all the treatments and control Under Hg treatments, the CAT activity(µmol H2O2/mg protein min) decreased as the concentrations increased and wassignificantly lower compared with the control. While the activity of APX (µmolAscorbate/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 ppmtreatment compared to the control. The application of HM treatments,significant increase in membrane damage (TBARS), but no significant differenceswere found in the production of extracellular H2O2 withthe control. These results suggest that the exposure of A. subterráneato HM induces lipid peroxidation, despite the activation of the enzymatic andnon-enzymatic defense. The oxidative stress could be due to another type of ROSrather H2O2. However, this specie managed to establishitself and tolerate different concentrations of heavy metals and could beconsidered as a potential specie for phytoremediation.