Probable transcription factor that binds to the L1 box DNA sequence 5'-TAAATG[CT]A-3'. Plays a role in maintaining the identity of L1 cells, possibly by interacting with their L1 box or other target-gene promoters; binds to the LIP1 gene promoter and stimulates its expression upon imbibition (PubMed:24989044). Acts as a positive regulator of gibberellins (GAs)-regulated epidermal gene expression (e.g. LIP1, LIP2, LTP1, FDH and PDF1) (PubMed:24989044). Functionally redundant to ATML1 (PubMed:24989044). Involved, together with HDG proteins (e.g. HDG1, HDG2, HDG5 and HDG12), in the regulation of flower organs development by promoting the expression of APETALA 3 (AP3) in the epidermis and internal cell layers of developing flowers (PubMed:23590515). Seems to promote cell differentiation (PubMed:25564655). Interacts with GAI/RGA2, RGA/RGA1/GRS, RGL2/SCL19 and ATML1 (PubMed:24989044). Binds to AIL7/PLT7, ANT, BBM and AIL1 (PubMed:25564655). Specifically expressed in the layer 1 (L1) of shoot meristems. Stimulated during seed imbibition (PubMed:24989044). Induced by gibberellins (GAs) and repressed by DELLA proteins in an ATML1- and PDF2-dependent manner (PubMed:24989044). Upon seed imbibition, increased GA levels in the epidermis reduce DELLA proteins (e.g. GAI/RGA2, RGA/RGA1/GRS and RGL2/SCL19) abundance and release, in turn, ATML1 and PDF2 which activate LIP1 expression, thus enhancing germination potential (PubMed:24989044). Plants missing both PDF2 and ATML1 have reduced levels of L1 box/ gibberellic acid (GA)-regulated putative targets, including LIP1, LIP2, LTP1, FDH and PDF1, in the presence of GA and during seed germination, thus leading to a delayed germination upon imbibition (PubMed:24989044). Double mutants pdf2-1 hdg1-1, pdf2-1 hdg2-3, pdf2-1 hdg5-1 and pdf2-1 hdg12-2 exhibit abnormal flowers with sepaloid petals and carpelloid stamens in association with a reduced expression of APETALA 3 (AP3) (PubMed:23590515). In plants missing HDG3, HDG7, HDG11, PDF2 and ATML1, increased cell division leading to cell overproliferation (PubMed:25564655). Belongs to the HD-ZIP homeobox family. Class IV subfamily. Truncated N-terminus.