Responsible for the deacetylation of lysine residues on the N-terminal part of the core histones (H2A, H2B, H3 and H4). Histone deacetylation gives a tag for epigenetic repression and plays an important role in transcriptional regulation, cell cycle progression and developmental events. May be involved in flowering induction. Histone deacetylases act via the formation of large multiprotein complexes. H2O + N(6)-acetyl-L-lysyl-[histone] = acetate + L-lysyl-[histone] Binds 1 zinc ion per subunit. Low expression in flowers. Belongs to the histone deacetylase family. HD type 1 subfamily. Extended C-terminus.