Sucrose Metabolism in NaCl-Treated Calli from Lycopersicon esculentum, L. pennellii and their Interspecific Hybrid

Abstract

Summary The enzyme activities of sucrose metabolism were determined in control and salt-(140 mM NaCl)treated calli from leaves, stems and roots of the cultivated tomato Lycopersicon esculentum cv. P-73, the wild species L. pennellii and their interspecific hybrid. Taking into account the apoplasmic contents, the NaCl-sensitive tissues (calli from L. esculentum , calli from leaves of the hybrid) accumulated less Na + and Cl − and more total soluble sugars than the NaCl-tolerant calli (calli from L. pennellii , calli from stems and roots of the hybrid). Sucrose hydrolysis, via acid invertase, and hexose phosphorylation, via glucokinase, decreased more in the salinized sensitive tissues than in the tolerant ones. The interconversion between Glc-6P and Glc-1P, via phosphoglucomutase, sucrose synthesis, via sucrose phosphate synthase and the enzyme activities of glycolysis or the pentose phosphate pathway were not coupled with the NaCl-tolerance degree of the tissues. Under control and salt-conditions, the ADP-glucose-pyrophosphorylase capacities of the tolerant tissues were 20- to 50-fold higher than those of the sensitive ones. Relations between the magnitudes of sucrose metabolism enzymes or the sugar levels and the salt tolerance of the heterotrophically grown calli are discussed.