Uranium uptake and stress responses of in vitro cultivated hairy root culture of Armoracia rusticana.

摘要

In this study, the accumulation of uranium was investigated in hairy root cultures of Armoracia rusticana under in vitro conditions in presence or absence of phosphates in the cultivation medium. The presence of phosphate has a stimulating effect on both growth of culture and accumulation of uranium. More than 98% of uranium disappeared from the medium (initial concentration 0.5 mM uranium) in presence of phosphates compared to 86% of uranium from the medium without phosphates. The accumulation of uranium was a very fast process based on simple or facilitated passive diffusion. The pH optimum of the culture growth and uranium accumulation was about 4.6 and the culture was able to adapt the pH value of the cultivation medium in a time frame of 24 hours. An increase of uranium uptake by adding cadmium or nickel to induce phytochelatine production had no effect. The presence of uranium, nickel and cadmium resulted in oxidative stress which is illustrated in this study by increases of peroxidase and glutathione-S-transferase activities.