Figure 4.

Concentration-dependent uptake of ⁶⁵Zn²⁺ in intact bread and durum wheat roots. Uptake solutions contained 250 nm EDTA and varying concentrations of ⁶⁵ZnSO₄ (50–800 nm). Zn²⁺ activities shown on the x axis were calculated using the speciation program GEOCHEM-PC. Data points and bars represent means and se values of four replicates. Error bars do not extend outside some data points. Inset, Low Zn²⁺ activity data points plotted on expanded axes. fr wt, Fresh weight.