FIGURE 1.

Mean photosynthetic yield plus standard error for the three species in spring and autumn: Myriophyllum aquaticum (A in spring and B in autumn), Egeria densa (C in spring and D in autumn), and Ceratophyllum demersum (E in spring and F in autumn). Treatments are denoted by white squares for leaf extract treatments, black squares for root extract treatments, white triangles for leaf leachate treatments, black triangles for root leachate treatments, and black circles for control series. Symbols marked with the same letter are not significantly different for treatment factors within the same period (p > 0.05), according to Mann–Whitney–Wilcoxon pairwise comparisons significance test adjusted by the Benjamini-Yekutieli correction.