Fig. 7. The relationship between amount of Ni extracted in four consecutive saturation extracts obtained from the Quarry, Welland, and Brockman soils, and the amount of Ni phytoextracted by shoots of A. corsicum and A. murale. Error bars represent ±standard errors. Soil pH treatments (Brockman acidified, Quarry calcareous, Welland calcareous) resulting in the highest shoot Ni concentrations attainable on each soil were selected for this graph.