Involved in lignin biosynthesis in the floral stem. Catalyzes the final step specific for the production of lignin monomers. Catalyzes the NADPH-dependent reduction of coniferaldehyde, 5-hydroxyconiferaldehyde, sinapaldehyde, 4-coumaraldehyde and caffeyl aldehyde to their respective alcohols. (E)-cinnamyl alcohol + NADP(+) = (E)-cinnamaldehyde + H(+) + NADPH Binds 2 Zn(2+) ions per subunit. Aromatic compound metabolism; phenylpropanoid biosynthesis. Homodimer. A number of isoforms are produced. According to EST sequences. Expressed at the lateral root initiation sites, in the vascular tissues of the primary lateral root and the root caps. Expressed in the hypocotyl, cotyledon and leaf veins, apical meristem region, at the base of the trichomes, hydathodes and cauline leaves. In stems, expressed in the cells associated with the vascular cambium, interfascicular cambium and the developing xylem. Expressed in the vascular strand of petals and sepals, anthers, stamen filaments, stigma in flowers, and abscission, style and stigmatic regions of siliques. Reduced lignin content and rigidity of the floral stems. Belongs to the zinc-containing alcohol dehydrogenase family.