Pollination is one of the most important steps during fertilization and sexual reproduction in plants,and numerous cell-cell interaction events occur between the pistil and the pollen grain/tube during this process.The pollen-stigma interaction is a highly selective process which leads to compatible or incompatible pollination.Previous studies in Solanaceae,Papaveraceae,and Brassicaceae provided some important insights into pollen-stigma recognition in self-incompatible systems.In recent years,considerable data have been available regarding pollen-stigma interaction during self-compatible pollination.In this review,we focus on discussing current knowledge on stigma factors that regulate pollen-stigma interaction in self-compatible systems in comparison with self-incompatible systems.