Changes Related to Salt Tolerance in Thylakoid Membranes of Photoautotrophically Cultured Green Tobacco Cells

Abstract

A line of cultured tobacco cells (Nicotiana tabacum cv. Samsun NN) was established that was able to grow photoautotrophically in a medium that contained 0.2 M NaCl or in a medium without NaCl. Thylakoid membranes of the NaCl-adapted cells had higher oxygen-evolving activities, on the basis of chlorophyll, than those of unadapted cells. Furthermore, the oxygen-evolving activities of thylakoid membranes from NaCl-adapted cells were more tolerant to high concentrations of NaCl than those from unadapted cells. Glycinebetaine at 1 M protected the oxygen-evolving activity of thylakoid membranes from unadapted cells but not that from adapted cells. Examination of the dissociation of 23-kDa and 33-kDa polypeptides from the water-splitting complex of photosystem II at high concentrations of NaCl indicated that the affinity with which the 23-kDa polypeptide was bound to thylakoid membranes of salt-adapted cells had been altered.