Several abiotic stresses including salinity impact plant growth and reduce the productivity of many plants and field crops. Plantlets produced in vitro by tissue culture technique offer a direct and fast approach to investigate the mechanism of stress adaptation. The present study estimated the survival percentage of two potato (Solanum tuberosum L.) cultivars (Spunta and Valor) under salt stress as abiotic stresses. Some biochemical alterations and ultrastructural responses of plantlets were examined. Moreover, genetic diversity was also studied using RAPD technique. The results showed that, with the increase of external stress there was a significant decrease in the survival percentage, significant accumulation of osmoprotectants (proline) and induction of DNA damages. Furthermore, there were closing of stomatal apertures, changes
in chloroplast ultrastructure and cell intercellular spaces markedly decreased. Additionally,
high salt stress (150 and 200mM NaCl) caused complete inhibition of plantlet growth. The
present work provides insight view for the adaptation of potato plantlets to salt stress through
accumulating of osmoprotectants and change in molecular and ultrastructure traits.