Transcription factor that specifically binds AT-rich DNA sequences related to the nuclear matrix attachment regions (MARs) (By similarity). Acts redundantly with AHL18, AHL22 and AHL27 in the regulation of flowering and regulation of the hypocotyl elongation (PubMed:19517252). Acts redundantly with AHL27/ESC to modulate hypocotyl growth inhibition in response to light (PubMed:18088311). Homodimer. Interacts with AHL5, AHL12, AHL25, AHL27, TCP4, TCP13 and EF114. Expressed in the hypocotyl and the vascular tissue of seedling. The PPC domain mediates interactions between AHL proteins. AHL27 and AHL29 double mutant exhibit a long hypocotyl phenotype in the light. Overexpression of AHL29 results in altered cell expansion dynamics and delayed senescence.