BIOCHEMICAL INDICATORS OF SALINITY TOLERANCE IN PROSOPIS STROMBULIFERA

LUNA, MARÍA VIRGINIA; LLANES, ANALÍA SUSANA; REGINATO , MARIANA ANDREA; BERTAZZA, GIANPAOLO

Rosario, Santa Fe

Simposio; VII Reunión Latinoamericana y XXVII Reunión Argentina de Fisiología Vegetal; 2008

Sociedad Argentina de Fisiología Vegetal

P. strombulifera is an interesting model plant to study plant tolerance to extreme salinity conditions. Growth parameters, pigments and ion content were differentially affected by iso-osmotic concentrations of NaCl, Na2SO4 and their combination. Growth was stimulated up to Ψo -1.9 MPa (500 mM) NaCl, but this species was much less tolerant to Na2SO4 showing growth inhibition and toxicity simptoms. When both salts were combined,the growth curve was intermediate between those with each monosaline solution showing toxicity alleviation. Anion accumulation was much lower than cation content suggesting that non-ionic compounds account for osmorregulation andelectrochemical balance. Aminoacids, proteins, sugars, polyalcohols,polyamines and jasmonates were detertmined. High proline accumulation with all treatments was considered a stress metabolic signal not necessarily indicating salt tolerance. There was no increase in glycinbetaine levels in response to any salt. Only NaCl caused extra total protein synthesis at Ψo -2.6 Mpa; SO42- treated plants had reduced protein content while bisaline treated plants had an intermediate value.total soluble acrbohydrates increased proportionally to salinity but changes in the partitioning root/shoot were obseved. Polyols analysis showed mannitol accumulation at mederate and high salinity only in NaCl treated plants leaves, while SO42- and bisaline treated plants produced sorbitol; in the presence of NaCl there was not sorbitol production. Inositol was not detected with any treatment suggesting a rapid conversion to pinitol, wich accumulated near 280 % more in salt treatments than in controls. Thus, sorbitol synthesis maybe a manifestation of carbon metabolism disorder under SO42- treatments, and the combination of mannitol and pinitol, apotential biochemical indicator of salt tolerance in this species. 12-oxophytodienoic acid (OPDA) and jasmonic acid (JA) decreased under salinity, but hydroxilated forms 11-hydroxi-JA and 12-hydroxi-JA increased. Putrescine content as well as 1,3-diaminopropane were highly increased with all salinity treatments suggesting a rapid polyamine metabolism, not related with salt tolerance in this specie.