| The experiment was conducted to evaluate in vitro the tolerance of five citrus rootstocks (Sour orange , Cleopatra mandarin , Troyer citrange , Volkamer lemon and Swingle Citrumelo ) to NaCl according to the effects of NaCl on their morphological characters and biochemical changes in multiplication stage. Double-node microcuttings were excised from proliferating shoot and cultured in proliferation medium ( MS + 2 mg BA + 0.1 mg NAA / L ) supplementing with four different NaCl concentrations (0, 50, 100, 150 mM) for four weeks as a factorial experiment in Complete Random Design(CRD) with two factors, rootstocks and levels of NaCl,. At the end of experiment, survival percentage (viability of culture) , proliferation ratio (number of shoots / explant ) , shoot length , number of leaves per shoot ,and total chlorophyll content were measured. The data showed that there were significant effects for NaCl in the morphological and biochemical parameters with the increase of NaCl concentrations in multiplication medium. Also, it was clear that the survival percentage , proliferation ratio , shoot length , number of leaves per shoot , and total chlorophyll for all rootstocks were decreased due to the increase of NaCl concentrations in multiplication medium . On the other hand, results showed a difference in the response of citrus rootstocks to stress resulting from the addition of NaCl in the medium of multiplication, the results revealed that the Cleopatra Mandarin rootstock was super on the other |