Catalyzes the formation of flavonols from dihydroflavonols. It can act on dihydrokaempferol to produce kaempferol, on dihydroquercetin to produce quercitin and on dihydromyricetin to produce myricetin. In vitro catalyzes the oxidation of both enantiomers of naringenin to give both cis- and trans-dihydrokaempferol. 2-oxoglutarate + a (2R,3R)-dihydroflavonol + O2 = a flavonol + CO2 + H2O + succinate 2-oxoglutarate + a (2S)-flavan-4-one + O2 = a (2R,3R)-dihydroflavonol + CO2 + succinate Binds 1 ascorbate molecule per subunit. Binds 1 Fe(2+) ion per subunit. Secondary metabolite biosynthesis; flavonoid biosynthesis. Expressed in young seedlings (at protein level). Expressed in roots, emerging leaves, shoot-root transition zone, trichomes, flowers and siliques. In cotyledons, expressed mostly on the adaxial side and only in guard cells on the abaxial side. By light, auxin and 1-aminocyclopropane-1-carboxylic acid (ACC). Accumulation of anthocyanins and glycosylated forms of dihydroflavonols, and drastic reduction of kaempferol, quercitin and favonol glycosides. Belongs to the iron/ascorbate-dependent oxidoreductase family.