Aminoacid changes in leaves and roots of tomato (Solanum lycopersicum) during salt stress

Abstract

Tomato seedlings were exposed to 100 mM NaCl during 10 days. NaCl stress led to about 40% and 20% decrease in leaf and root biomass, respectively. Accumulation of Na+ and Cl− ions was concomitant with NH4+ contents increase in stressed leaves and roots. While total aminoacids contents rapidly increased by salt in both organs, they recovered control value in the leaves at the end of treatment. In leaves, NaCl stress increased proline and serine contents, lately associated with accumulation of y—aminobutyric and asparagine. Slat—treated roots showed 2-fold higher contents of serine, glycine, glutamine and GABA. Asparagine became the most abundant aminoacid, accounting for 26% of total aminoacids in the treated roots. These disturbances in the aminoacids composition reflect a new distribution of internal nitrogen compounds, building up an aminoacid pool with high N to C ratio and avoiding thus an ammoniacal intoxication. Proline, Asn and GABA are useful for nitrogen transport to developing tissues and protect against osmotic and oxidative stresses during salt stress. © 2010, Taylor & Francis Group, LLC.