Figure 2.

Morphometric and electrolyte leakage assays of reil1-1 reil2-1 at low temperatures. reil1-1 reil2-1 and Arabidopsis Col-0 wild-type plants were compared after the shift from 20°C to either 10°C (left) or 4°C (right). A, Leaf number. Mutant and wild-type plants differed significantly after 2 weeks at either 10°C or 4°C (*, P < 0.05; means ± sd of n = 3–10 plants). B, Rosette area. Mutant and wild-type plants differed significantly after 2 weeks at either 10°C or 4°C (*, P < 0.05; means ± sd of n = 3–10 plants). C, Electrolyte leakage assay for the quantitative assessment of freezing tolerance (LT₅₀, temperature of 50% normalized electrolyte leakage). The mutant did not show increased electrolyte leakage compared with Col-0 (*, P < 0.05; means ± se of n = 4–8 pools of leaves; n.d., not determined). Experimental designs were according to schemes C and D in Figure 1. Mutant and wild-type plants were shifted at developmental stage ∼1.10 (Boyes et al., 2001). Week-0 plants were cultivated at 20°C and assayed immediately before the temperature shift. Significance was tested using the heteroscedastic Student’s t test.