Effect of Salt Stress on Na Accumulation, Antioxidant Enzyme Activities and Activity of Cell Wall Peroxidase of Huckleberry (Solanum scabrum) and Eggplant (Solanum melongena)

Understanding the adaptive mechanisms to salinity stress is an important prerequisite for crop improvement and sustainable production. The objective of this study was to compare the adaptation of huckleberry and eggplant to salinity in terms of total dry weight, malondialdehyde (MDA) content, the activities of catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR), soluble peroxidases (sPOD) and peroxidases ionically-bound to cell wall (cwPOD) and Na+ and K(+)concentrations. Growth was found to be more reduced in eggplant (63% reduction) than huckleberry (51% reduction). Na+ concentration was 2.5-fold higher in leaf of eggplant than huckleberry. The MDA content significantly increased in root and leaf of eggplant, but remained unchanged in huckleberry. In the leaf of huckleberry, cwPOD alone was significantly enhanced by salt stress, whereas in the root all the enzymes except CAT were significantly elevated. In eggplant on the contrast, cwPOD activity tended to decrease in leaf and root, whereas CAT markedly increased in the leaf, but sharply declined in the root. APX activity in eggplant slightly increased in both root and leaf while sPOD significantly increased in the root but remained unaltered in the leaf. These results suggest that Na+ exclusion in the leaf blade and greater antioxidant activity in the root constitute important adaptations to salt stress in huckleberry. Particularly, cwPOD activity in the leaf and root of huckleberry suggest a dual role in the adaptation; mainly reactive oxygen species detoxification in leaf and enhanced lignin deposition in root, which functions in controlling root-to-shoot Na+ delivery. (C) 2015 Friends Science Publishers