Figure 7.

Arabidopsis mutants of AtCNGC2 and AtCNGC4 are chilling and freezing susceptible. A and B, Phenotypes (A) and quantification (B) of hypocotyl elongation of cngc2 and cngc4 in the dark at 22°C (for 36 h) and 6°C (for 4 d). Data represent means ± sd from three biological replicates, each of which had at least 15 seedlings. C and D, Phenotypes (C) and quantification (D) of rosette growth of the wild type, cngc2, and cngc4 grown on soil at 22°C for 3 weeks and at 6°C for 45 d. Data represent means ± sd from three biological replicates with 10 plants per replica. Double factor variance analysis shows interaction between genotype and temperature. E to G, Phenotypes (E) and survival rate quantifications (F and G) of the wild type and mutants after −8°C treatment for 3 h followed by a 1-week recovery. Data represent means ± sd from nine repeats (one pot per repeat) for each genotype. Asterisks indicate significant difference by Student’s t test (**P < 0.01). Scale bars = 0.5 cm (A), 1 cm (C and D), and 2 cm (E).