Determination of Tolerance of Two Apple Rootstocks to Different Concentrations of Sodium Chloride Under In Vitro Conditions

Tolerance of two apple rootstocks (Gami and M26) was evaluated at different concentrations of sodium chloride in vitro conditions. Micro plants grown under MS medium culture were transferred to Knoudson–C culture medium devoid of Na and Cl ions. Concentrations of NaCl in the knoudson-C culture medium were 0, 20, 40, 60, 80 and 100 mM/l. Six weeks after culturing, data were collected. The results indicated that the effects of rootstock, salt concenteration and interaction of rootstock and salinity on evaluated characteristics were significant, but the interaction of rootstock and salinity exerted no significant effect on dry weight of roots. As the NaCl concentration in the culture medium increased, the length of shoots and roots, fresh and dry weight of shoots and roots, number of roots and leaves significantly decreased, but the percentage of yellowing of leaves and sodium uptake, as well as proline and soluble sugar contents increased. According to the results, means of shoot and root length, fresh and dry weight of shoot and root, number of leaves and roots, proline and soluble sugar contents were higher in Gami apple rootstock than in M26, but percentage of dried leaves and sodium uptake were lower in Gami rootstock than in M26. According to the obtained results Gami was more resistant than M26 rootstock to salt stress under in vitro conditions.