NACL STRESS-INDUCED ORGANIC SOLUTE CHANGES ON LEAVES AND CALLI OF LYCOPERSICON-ESCULENTUM, L-PENNELLII AND THEIR INTERSPECIFIC HYBRID

A comparative study between leaves of whole plants and calli from leaf was carried out in Lycopersicon exculentum (L.) Mill., L, pennellii ( Correll) D'Arcy and their interspecific hybrid with the objective to o btain knowledge of the NaCl stress-induced changes in the total solubl e sugars, organic acids, free amino acids and soluble proteins. Simila r growth responses to salinity were found in leaf and calli of both pa rents and their hybrid, because leaf dry weight and the relative growt h rate of calli increased in L. pennellii and decreased in L. esculent um and the hybrid at 70 mM NaCl with respect to controls. Total solubl e sugar and organic acid contents were much higher in calli than in le aves. Sugars decreased with salinity in calli of L. pennellii and incr eased significantly in L. esculentum and the hybrid. However, these so lutes are not related to salt tolerance in the leaves of whole plants. In general, total organic acids decreased with salinity in both paren ts and their hybrid at both organizational levels. An increase in tota l free amino acid contents with salinity was observed at both organiza tional levels in L. esculentum and the hybrid, while it was only found in leaves of L. pennellii, although to a lower degree. These increase s were mainly due to proline and GABA in salt-sensitive L. esculentum and the hybrid, and Asn + Glu in L. pennellii. On the basis of these r esults, proline and GABA contents may be useful as possible salt-injur y sensors, in both leaf and calli from leaf. Moreover, the relation be tween sugar content and salt-tolerance degree in calli indicates that leaf-cell culture is a good method to study the implication of sugar m etabolism in salt-tolerance responses.