A. calamus had the highest average daily photosynthetic rate (9.8 mmol CO2m2 s1), followed by P. australis (9.2), while V.
zizanioides showed the lowest value (6.2), whichwas significantly lower than those of A. calamus and P. australis (P < 0.05). All
species showed a similar mono-peak daily pattern in photosynthetic rates, with the maximum photosynthetic rates occurring
generally between 11:00 and 13:00 (Fig. 2).