Experiments at low Au concentration over a period of 360 h show that although the plants were totally necrotic after 72 h, they continued to absorb Au in appreciable amounts. In general, the uptake of Au by MS and BJ shoots increased with time exposure.The data clearly suggest that at shorter exposure times, the absolute quantity of Au accumulated by BJ shoots was 3–4 orders of magnitude greater than for MS shoots (Fig. 3c). At longer exposure times the accumulation of Au by BJ was greater still, however it was only twice the uptake by MS shoots. Thus BJ is a better accumulator of Au at low concentrations and longer exposure times.