Plant uptake was calculated using Si concentrations multiplied
by the biomass production (Fig. 3). Shoot uptake increased significantly
in applications greater than 10-ton ASi ha−1, being 63% larger
in the 15-ton Si ha−1 treatment than in the control pots. However,
this effect was not significant for roots.
3.1.3. Metal distribution in plants
Cadmium concentrations in the plant shoots significantly
decreased with increasing ASi supplementation (Fig. 4A), while
the opposite trend was observed for roots. However, the shoot
to root ratio remained constant for all treatments (Table 2).
Contrarily, when the total Cd content from both shoots and roots
was calculated (Fig. 4B), the Cd amount in shoots was similar
to that of control plants, while the root total uptake was still
significantly larger with the largest Si application. The other metal
concentrations (Zn, Cu and Pb) were larger in roots than in shoots