Salt tolerance of mango grafted on rootstocks and antioxidant enzyme responses

Four mango (Mangifera indica L.) rootstocks (Sukkary, Zebda, 13/1 and Peach) were selected and grafted with the scion Keitt to assess and identify their salt tolerance as foreign and local mango rootstocks. Saline treatment included irrigation with saline water at 1000, 2000 and 3000 ppm in addition to the untreated one (control) were tested on plant survival, leaf and root Na/K ratio and leaf content of antioxidant enzymes of peroxidase (POD) and poly phenyl oxidase (PPO) isozymes. The obtained results showed that salinity treatments decreased the survival percentage of Peach and 13/1 rootstocks followed by Sukkary were more tolerant, meanwhile Zebda rootstock considered less tolerant to salinity. The results revealed that the relative sensitive of grafts on Zebda rootstock was due to low Na/K ratio in the leaves compared with that on more tolerant ones on Sukkary, 13/1 and Peach rootstocks. The isozymes analysis of POD and PPO enzymes indicated that the low tolerance of "Zebda" rootstock could related its low content of these enzymes especially with the control treatment when compared with that in other tested rootstocks to the other rootstocks.