At low solution concentrations (5–2

At low solution concentrations (5–20 ppm) the roots transport greater quantities of Au to the shoots in BJ than MS (Fig. 3b). Au mobility to shoots is greater at lower concentrations indicating lower retention in the roots. At higher concentrations Au transport occurs at slower rates as indicated in Fig. 3b. A maximum TF of 0.14 was achieved at the lowest solution concentration studied (5 ppm) after 48 h exposure time. The TF for BJ decreased in general across the lower concentrations (5–20 ppm) and increased with an increase in concentration (40–80 ppm). Transport of Au to shoots in MS was different from BJ; the results show less transport compared to BJ. Amaximum of 0.087 TF was achieved at 5ppm concentration and 48 h exposure time. MS showed similar trends to BJ with a decrease in TF from 5 to 20ppm and an increase in TF from 20 to
80 ppm