Physiology and biochemistry of Prosopis strombulifera under salinity. Are halophytes tolerant to all salts?

REGINATO , MARIANA ANDREA; LLANES, ANALÍA SUSANA; GARELLO, FABIÁN; DEVINAR, GENOVEVA; VARELA, CELESTE; MASCIARELLI, OSCAR; LUNA, MARÍA VIRGINIA

La Plata

Congreso; Congreso Latinoamericano de Fisiología Vegetal y XXX Reunión Argentina de Fisiología Vegetal; 2014

Prosopis strombulifera was chosen as a plant model to investigate the effects of Na2SO4, NaCl and their iso-osmotic mixture on the physiological and biochemical responses, with main focus on endogenous polyphenols and pigment synthesis. Treatment with Na2SO4 increased lipid peroxidation (MDA) and H2O2 production in tissues, and an increase in flavonoids and antioxidant activity. Also, Na2SO4 treatment decreased total photosynthetic pigments. NaCl treatment did not affect MDA, H2O2, pigments and polyphenols synthesis. The increase in lipid peroxidation and H2O2 production when SO42- anion is present in the growth solution indicates a strong oxidative stress in these plants, differently from NaCl treatment. SO42- treated plants showed a remarkable decrease in Fv/Fm at the end of the experiment and higher xanthophyll de-epoxidation state. If there are inactive units in PSII, there is great potential for ROS formation. When other ROS-detoxifying systems such as the xanthophyll cycle are not effective enough, as in the case of Na2SO4-treated plants, polyphenols production is increased as an alternative detoxifying system.These observations indicate a fundamental role of polyphenols in the protection of the photosynthetic apparatus under severe stress caused by SO42- at the expense of growth. Ionic interactions between the different salts modify the physiological responses elicited by the individual salts.