Constitutive photomorphogenic phenotypes of HFR1-ΔN105-overexpressing transgenic Arabidopsis. A, Fluence rate responses of inhibition of hypocotyl elongation under FR light. The data are expressed as average relative hypocotyl length from at least 20 seedlings, normalized to their respective hypocotyl length in darkness ± sd. The average length of dark-grown seedlings was 9.8, 8.9, and 10.2 mm for wild-type, hfr1HFR1 ox-39, and hfr1-201 seedlings, respectively. Error bars = sds. WT, Wild type. B, Hypocotyl elongation phenotypes in wild-type and transgenic plants. The seedlings were grown for 4 d under FR light (21 μW cm-2) or in darkness. Each measurement was performed on at least 20 seedlings. The data are expressed as average hypocotyl length ± sd. C, Morphology of representative seedlings. The seedlings were grown for 5 d in darkness. Scale bar = 5 mm. D, RNA gel-blot analysis of wild-type and transgenic plants overexpressing full-length HFR1 or HFR1-ΔN105. Total RNA (10 μg) was loaded and subject to RNA gel-blot analysis. The blot was hybridized with a 32P-labeled HFR1-ΔN105 probe. The 18S rRNA was used as a loading control. The signals were visualized with a phosphor imager (FLA2000, Fuji, Tokyo).