Figure 2. Growth of the three duckweed species in the four zinc
(Zn) treatments over 17 days. Shown are means and standard errors for
each sampling date, across settings and compositions. Orange
lines, 0 mg/ L Zn, blue lines, 0.45 mg/L Zn, green lines, 1.82 mg / L
Zn, yellow lines, 11.35 mg/L Zn.