Morphological, physiological and biochemical adaptations of Eucalyptus citriodora seedlings under NaCl stress in hydroponic conditions

Salinity stress could be managed by the growth of economically important tree species. Adaptations of Eucalyptus citriodora to NaCl stress was investigated under different concentrations of NaCl (15-75 mM). After 2 and 6 months of treatments, data were recorded for growth performance (shoot and root length, leaf number and area), physiological attributes [chlorophyll(a) (Chl(a)), chlorophyll(b) (Chl(b)), total chlorophyll (TC), carotenoids, relative water content (RWC)] and osmolyte accumulation [proline, glycine betaine (GB) and trehalose] parameters. After 2 months, changes in morphological parameters of treated plants were negligible (1-1.8-folds) in comparison to control, which is correlated with 2-8-, 1.12-7.7- and 1.73-3.94-folds increase in GB, proline and trehalose contents, respectively. At 6 months, though there was plant mortality, 70-80 % decrease in TC contents and reduction in osmolyte contents but 20 % increase in RWC of stressed plants were monitored. Survival at higher salt concentrations with accumulation of sodium shows significant salt tolerance in this species.