Fig. 2.
—Phylogenetic position and physiological feature of psychrophilic algae. (a) Phylogenetic tree of 12 green algae inferred from 2,182 orthologous genes using concatenation and coalescent methods. The bootstrap support values and posterior probability scores are shown on the nodes from left to right; the two psychrophilic algae were colored in red. (b) C. reinhardtii, T. socialis, and C. sp. ICE-L were cultured in their optima temperature (up) and low temperature condition (−5 °C) (down). (c) Photosynthetic efficiency (Fv/Fm) of C. reinhardtii, T. socialis, and C. sp. ICE-L at two time points: 0 h (before cold treatment for 24 h) and 48 h (back to optimal temperature for 24 h after cold treatment); *The significant difference between control and treatment (P < 0.05). Abbreviation: C. sp. ICE-L, Chlamydomonas sp. ICE-L; T. socialis, Tetrabaena socialis; and C. reinhardtii, Chlamydomonas reinhardtii.