Manganese is the only ion for which concentrations in both
plants increase together with lead concentrations (Table 1). On
the other hand, the total Mn amounts per plant are reduced
(Table 2), which means that Mn uptake too is inhibited in
the presence of lead, although to a lower extent than other
ions. Manganese is involved in the production of oxygen from
water in photosynthesis (Haider et al., 2006). The decrease of
Mn amounts started at 1.5 mM Pb for wheat and only at
3 mM Pb for spinach. Manganese contents per plant were
much higher in spinach (18.6-fold) than in wheat.