Short-term solute changes in leaves and roots of cultivated and wild tomato seedlings under salinity

The daily variations of inorganic and organic solutes with salinity (140 mM NaCl) were determined in seedlings of cultivated tomato (Lycopersicon esculentum Mill.) and its wild salt tolerant relative L. pennellii (Correll) D'Arcy for 8 days, with the objective to identify physiological traits in either leaves or roots contributing to the salt tolerance. A greater accumulation of leaf Cl- and, especially, Na+ was found in L. pennellii than in L. esculentum, while root Na+ concentrations increased similarly in both tomato species over the salinization period. The changes induced by salinity on the Na/K and Na/Ca ratios were different in both tomato species; in leaves, the increases of both ratios with time of salinization were higher in L. pennellii than in L. esculentum, while in roots both ratios, mainly the Na/Ca ratio, increased more in L. esculentum than in L. pennellii in the time course. The accumulation patterns of total soluble sugars were also different in both tomato species: although a higher sugar accumulation was found in L. esculentum than in L. pennellii at the end of the salinization period, an earlier sugar accumulation occurred in leaves and roots of L. pennellii. The proline accumulation was greater in the cultivated than in the wild tomato species, and earlier in roots than in leaves, but in no case did it occur in the first days of salinization. gamma-aminobutyric acid (GABA) was the only amino acid that increased significantly from the beginning of the salt stress in leaves and roots of L. esculentum, which did not occur in L. pennellii.