Free polyamines levels in salinized seedlings of Prosopis strombulifera.

REGINATO M.; RUIZ O.; CASSAN F. AND LUNA V.

Villa de Merlo. San Luis. Argentina

Congreso; XXII Reunión Anual de la Sociedad de Biología de Cuyo y I Reunión de la Sociedad de Microscopia Argentina.; 2004

Sociedad de Biología de Cuyo

Alterations in polyamine levels especially putrescine (Put) in salt stressed plant tissues have been reported. Prosopis strombulifera is considered a halophytic plant for its anatomical and physiological features. Endogenous polyamines in halophytes had not been studied and was the objective of this work. Seedlings were grown hidroponically in Hoagland solutions with addition of 50 mmol/l NaCl and 38 mmol/l Na2SO4 for the respective monosaline treatments and isoosmotic mixtures of both salts for bisaline treatments. Salt pulses were additioned every 48 h until final osmotic potentials of –1, -1,88 and –2,6 MPa. Control plants were grown in Hoagland 25%. HPLC and fluorescence spectrophotometry were used to separate and quantify free polyamines as their dansyl derivatives. Put content in leaves increased considerably in all salt treatments, but mainly in bisaline treatment. Spermidine (Spd) increased in response to all sulphate containing treatments being accompanied by Cadaverina (Cad) and 1,3 diaminopropano (Dap) (uncommon polyamines in plants)  in the higher salinities, in coincidence with the appearance of toxic symptoms in the plants. This was not observed in NaCl treatments. Spermine (Spm) increased only in salt mixtures at the highest concentration. In roots, Cad and Dap were also detected in response to high salinity (-2,6 MPa, 700 mM NaCl and 538 mM Na2SO4). Put levels also increased with salinity but to lower levels than in leaves but Spd and Spm decreased with salinity, probably due to catabolism or conjugation.