Fig. 9.
Photosystem II efficiency Fv/Fm. (a) Zygnema sp. B (n = 3), (b) Zygnema sp. G (culture medium, 800 mM n = 3, 400 mM n = 2), (c) Zygnema sp. D (n = 3) and (d) Zygnema sp. E (n = 3) in culture medium (control) and after incubation in 400 mM and 800 mM sorbitol for 3, 6 and 24 h. Lower case letter indicate p ≤ 0.001. In Zygnema sp. B (a), the Fv/Fm value after incubation for 6 h in 800 mM sorbitol (lower case letter a, b) is significantly different to the Fv/Fm value after incubation in 400 mM sorbitol for 6 h (lower case letter a).