Regulates carpel specification in flower development. Severe or intermediate mutation in DL causes complete or partial homeotic conversion of carpels into stamens without affecting the identities of other floral organs. Interacts antagonistically with class B genes and controls floral meristem determinacy. Regulates midrib formation in leaves probably by inducing cell proliferation in the central region of the leaf. Detected during flower and leaf development. Expression in the flower meristem in the early stage of flower development. When carpel primordia begin to form, specific and uniform expression in carpel primordia. Expression in the central region of the leaf plastochron 1 (P1) primordia. Detected up to P4 stage, hardly detected in the P5 leaves. Belongs to the YABBY family.