Relation between salt tolerance and photosynthetic capacity and (in)organic solute concentrations of vitroplants of Lycopersicon pennellii and L-esculentum

The rate net of photosynthesis, the ribulose 1,5-bisphosphate carboxylase (RuBPCase), phosphoenolpyruvate carboxylase (PEPCase), enzyme of sucrose biosynthesis and Hill activities, and the mineral and organic (chlorophyll, soluble sugars, organic acids and amino acids) contents were measured in leaves of Lycopersicon esculentum and L. pennellii cultured in vitro on 50 mM NaCl or salt free media. Under such myxotrophic conditions, the wild species (L. pennellii) was more NaCl-sensitive than the domestic L. esculentum. Although Chi contents decreased in both salt-treated species, net photosynthesis decreased solely in salinized L. esculentum; moreover the wild species maintained higher RUBPCase, PEPCase and sucrose biosynthesis activities than the domestic species. The Hill activities in chloroplasts isolated from both species grown on saline media were enhanced compared to values in chloroplasts isolated from control plants. The NaCl sensitivity of myxotrophic L. pennellii would be Linked to a glycophytic behaviour resulting from a high soluble sugar accumulation, a decrease in inorganic nutrient (Na+, Cl-, K+) translocations and a restriction in the levels of organic acids linked to oxidative respiration.