Transcription activator that binds DNA on 5'-ACTCTAC-3' and promotes auxin homeostasis-regulating gene expression (e.g. YUC genes), as well as genes affecting stamen development, cell expansion and timing of flowering. Synergistically with other SHI-related proteins, regulates gynoecium, stamen and leaf development in a dose-dependent manner, controlling apical-basal patterning. Promotes style and stigma formation, and influences vascular development during gynoecium development. May also have a role in the formation and/or maintenance of the shoot apical meristem (SAM). Expressed in cotyledon tips, leaf primordia, hydathodes, stipules, and lateral root primordia and weakly at the edges of petals and sepals. No visible phenotype. Belongs to the SHI protein family.