Effect of different arsenic and phosphorus concentrations on osmolytes content of Isatis cappadocica

Arsenic is considered as one of the most important environmental contaminant compound. Some plant species can grow in arsenic contaminated soil and they are able to reduce arsenic toxicity. Nowadays، phytoremediation as a new and friendly environmental technique employs the use of plants to remediate contaminated soil. Previous studies showed that Isatis cappadocica is an arsenic hyperaccumulator plant. Accordingly، we conducted this experiment to compare the interaction of arsenic and phosphorus on osmolytes content of I. cappadocica for better understanding the mechanisms applied by this species. Therefore، the plants were grown for 6 weeks in a medium، embedded with combinations of 50، 200، 800 & 1200 μmol l−1 arsenic and 5، 50، 200، 800 & 1600 μmol l−1 phosphorus، respectively. The osmolytes content and the arsenic concentration of harvestable parts were determined. The highest concentration of arsenic was obtained in plants treated with 1200 μmol l−1 As and 5 μmol l−1 phosphorus. Increasing arsenic concentration in the medium lead to increase of osmolytes (soluble sugars، proline and protein). The ability of Isatis to accumulate more than 700 mg kg-1 arsenic in the shoots، illustrates the high resistance of this herb to arsenic and the existence of efficient mechanisms including accumulation of osmolytes.