Effect of Sodium Chloride on Tropane Alkaloids Accumulation and Proline content in Datura metel and D. stramonium callus cultures.

Plant tissue culture techniques were used to study the effect of NaCl on tropane alkaloids accumulation and proline content of both Datura metel and Datura stramonium. Callus cultures were established for both Datura species. However, MS medium supplemented with 1mg/l of both BA and NAA was the best for callus production in D. metel, while MS supplemented with 3 mg/l Kin and 1 mg/l 2, 4-D was the optimal medium for callus production in D. stramonium. Five NaCl concentrations (25, 50, 75, 100 and 125 mM) were used to test its effect on tropane alkaloids and proline contents in the produced callus. Total tropane alkaloids were extracted from both control and salt-treated calli and analyzed using HPLC. At 125 mM NaCl scopolamine and atropine concentrations recorded 8.5 and 11.5 folds higher than control of D. metel, while they recorded 2.5 and 3.5 fold higher than control of D. stramonium after one month of culture. Peroxidase activity was determined and results showed that D. metel recorded the highest enzyme activity at 100mM NaCl concentration, while D. stramonium callus showed the highest activity at 75mM NaCl. Proline content was increased by salinity in the rate of 0.326mM proline/25mM NaCl in D. metel, and in the rate of 0.1248 mM proline/25mM NaCl in D. stramonium. The results of this investigation showed that using plant tissue culture techniques to establish callus culture from both Datura species under NaCl stress is a powerful protocol for scopolamine and atropine accumulation improvement.