Effect of phosphorus on the concentrations of arsenic, iron and some other elements in barley grown hydroponically

Hydroponic barley (Hordeum vulgare L. cv. minorimugi) was treated with 10 μM arsenic (As) together with 500, 250, 50 and 0 μM phosphorus (P) for 14 days to observe the response of the seedlings. The plants were also treated with 0 μM As + 0 μM P. Iron (Fe)-plaque was visible in the roots under As-treated and P-depleted conditions. The intensity of reddish coloration in the roots decreased with increasing P in the media. However, reddish coloration was not found in the absence of both As and P. The results show that both As and P played a vital role in the formation of Fe-plaque. Additionally, Fe-plaque formation was dependent on the concentration of P in the media. Iron concentration in the roots of the As treated plants without P was higher than that observed in the roots treated with 0 μM As + 0 μM P which suggests that As may have been adsorbed with Fe on the surface of roots, forming Fe-plaque. Arsenic concentration in the shoots and the roots was low under 500 and 250 μM P conditions while high under 50 and 0 μ M P conditions. It was found that a higher concentration of P (50 μM; 5 times of As level) was required in the medium to reduce As concentration in the plant tissues.