Figure 6.

Macroscopic changes of duckweeds at high phenol concentrations: (A) at 500 mg L⁻¹, chlorosis is extensive; (B) at 750 mg L^-1 chlorosis is observed, but to a much lesser extent than at 500 mg L⁻¹ (A); (C) at 1000 mg L⁻¹, chlorosis is almost completely absent and the fronds appear to be darker green and smaller than at 750 mg L⁻¹ (B) and at 500 mg L⁻¹ of phenol (A).