Evaluation of the effects of different arsenic and phosphorus levels on chlorophyll and malondialdehyde content of Isatis cappadocica

Arsenic is considered as one of the most important environmental contaminant compounds. Arsenic is known to induce oxidative stress in plants by generating various reactive oxygen species and thus increased lipid peroxidation. Phosphorus has some physic-chemical similarities with arsenic which affects its metabolism in plant cell. Malondialdehyde (MDA) is a measure of lipid peroxidation in membrane damage index. In this study، the interaction of arsenic and phosphorus on chlorophyll content and MDA accumulation of I. cappadocica، as a newly-discovered As hyperaccumulator، were investigated in hydroponic experiment. Plants were grown 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 chlorophyll and MDA cnotent، hydrogen peroxide (H2O2) concentration، arsenic and phosphorus concentration and boimass 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. Increased levels of phosphorus led to reduction of arsenic concentration، which confirmed there was an interaction between these two elements in plant. Along with a marked increase in arsenic concentration in the media، a built up in (MDA) and (H2O2) were observed. The insignificant reduction in biomass and chlorophyll content، illustrated the high resistance of this herb to arsenic.