EFFECT OF ARSENIC ON GERMINATION, PHOTOSYNTHESIS AND GROWTH PARAMETERS OF TWO WINTER WHEAT VARIETIES IN IRAN

Effects of different arsenic (As) concentration (030mg L1) on seed germination, root tolerance index, relative shoot height, root and shoot biomass, photosynthetic pigments and arsenic accumulation in two wheat varieties were investigated. Low concentrations of arsenic (02.5mg L1) stimulated germination percentage, shoot and root elongation, plant biomass as well as chlorophyll content as compared with control, however, these factors all decreased gradually at high concentrations of arsenic (530mg L1). Zarin' variety had a significantly higher tolerance to arsenic than Sardari.' Arsenic accumulation by plants root and shoot increased with the increasing arsenic concentrations in medium, which Zarin' had a higher ability to absorb and translocate arsenic to the shoots. Root accumulated more arsenic than shoot. The similar trend of chlorophyll content and wheat growth under different arsenic concentration suggesting that arsenic toxicity affects the photosynthesis which ultimately results in the reduction of wheat growth and yield.