Physiological and antioxidant enzymatic activity responses of rootstock of sapodilla to salinity stress

Sapodilla is one of the important fruit crops in tropical area which has problem with seed germination. So Manilkara hexandra (kherol) is generally used as a rootstock for sapodilla. This experiment was performed to assess the morphological changes and antioxidant enzymatic activity of Manilkara hexandra seedling under salinity condition. A pot experiment was carried out in a greenhouse using different concentrations of seawater (3, 6, 9, 12 ds/m) on the one-old age seedling and fresh water used as control. The experimental design was a Completely Randomized Design (CRD) experiment. Result showed that seawater irrigation had no significant effect on length and volume of root. However, fresh weight of leaf, stem and root decreased significantly by increasing seawater concentration. POD and CAT antioxidant enzymes showed the similar trend under stress and their activities increased strongly. However, APX activities increased gradually by increasing salinity level.This dramatic increase might show that POD and CAT are a major enzyme among antioxidant enzymes examined in Manilkara hexandra (kherol) under salt stress. Thus, antioxidant defense system induced by salinity plays important role in this plant under salinity stress.