Trends in leaf concentrations of Ca and P along the pollution-induced soil gradient.

<p>Average Ca concentrations in weed vegetation and cereal crop (a); average Ca (b) and average P (c) in the three major ecological groups of species along the induced soil gradient. Species groups are defined by Indicator Species Analysis (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0114290#pone-0114290-g002" target="_blank">Figure 2</a>). Average group elemental concentrations were calculated by weighting concentrations in each species by the relative proportion of a species in group biomass per m². Leaves were sampled when crop was at milky ripeness phase (Z71–75).