Figure 4.

Analysis of difF mutant flowers. (A) Phenotype of the difF-W2090 allele in a hf1⁺rt⁺ (Upper) and a hf1⁺rt⁻ background (Lower). The arrows indicate a revertant (difF⁺) sector. (B) PCR analysis of the difF locus in homozygous mutable (m/m) and revertant (+/m) sectors in flowers with different hf1, hf2, and rt genotypes. The intermediate size fragments are heteroduplexes consisting of a difF∷dTph1 and a difF⁺ strand, which are generated by the PCR. (C) HPLC analysis of anthocyanin aglycones accumulated in the same sectors. The identity and the molar ratios of the anthocyanin peaks were established by chromatography of pure compounds: del, delphinidin; cya, cyanidin; peo, peonidin; mal, malvidin. (D) F3′5′H enzyme activity in the petal limbs of plants with the indicated phenotype selected from the backcross populations.