Influence of NaCl salinity on the behavior of hydrolases and phosphatases in mulberry genotypes: Relationship to salt tolerance

Two genotypes (Tr4 and Tr10) of mulberry(Morus indica) were cultured using aqueous solutions that contained different concentrations of NaCl (0 to 30 mM). Electrical conductivity (EC) values ranged from 0.52 to 4.60 mS cm-1, with a pH of 7.0. Analyses were conducted to envisage the effects of NaCl salinity on some hydrolytic enzymes. Neither nitrate reductase nor nitrite reductase activities were affected by salt treatment in roots and leaves of either genotype. The activities of β- and α-amylases were higher in leaves than in roots. Both alkaline and acid phosphatases exhibited significant increases in the roots and leaves of Tr4; no such trend was observed in Tr10. The levels of peroxidase and Superoxide dismutase increased quite significantly in the leaves as well as the roots of both genotypes. Increased enzymatic activities may suggest a stress-tolerant nature for these genotypes against NaCl toxicity. This was also evidenced by the unaffected levels in percent rooting, chloroplast pigments, osmoprotectants, nitrogenous compounds, and some biomolecules, as had been observed in earlier studies.