NA2SO4 AND NACL DIFFERENTIALLY MODULATE THE ENZYMATIC ANTIOXIDANT SYSTEM IN Prosopis strombulifera.

CAVALLIN, VANINA; REGINATO , MARIANA ANDREA; FURLÁN, ANA; GARELLO, FABIÁN; CASTRO, STELLA; LUNA, MARÍA VIRGINIA

Mendoza

Congreso; XXXIV Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2016

Prosopis strombulifera (Lam) Benth, is a spiny shrub especially abundant in the salinized areas of central Argentina with soils characterized by similar proportions of NaCl and Na2SO4. These species showed a halophytic response to NaCl, but in contrast, a strong growth inhibition at lower Na2SO4 concentrations. In the present study we evaluated the oxidative damage in tissues and the antioxidant response caused by NaCl, Na2SO4 and their iso-osmotic mixture in these species. We found that Na2SO4 induced an important oxidative damage with significant increase in malondialdehyde (MDA) and hydrogen peroxide (H2O2). Also, an intense staining for H2O2 and O2-? was observed in Na2SO4-treated plants by using histochemical detection, whereas NaCl-treated plants presented a slight staining. In Na2SO4-treated plants, a gradual decrease in catalase (CAT) activity was observed in roots, while in leaves showed a marked increase at high salinity. In contrast, a strong superoxide dismutase (SOD) activity was observed, with increases in both leaves and roots, with activity levels much higher than in NaCl-treated plants. It seems that CAT plays an important role in early detoxification of H2O2 in roots, while SOD would have a predominant role in leaves, reflecting its important role in the anion superoxide detoxification. It seems that at higher salt concentrations the antioxidant enzymatic activity allows H2O2 to act as a stress signal to trigger adaptive physiological responses such as early suberification and lignification in roots. An intense activity principally of SOD in Na2SO4-treated plants indicates an effort of plants to counteract the severe oxidative stress caused by this salt.