Plant somatic cells have the capability to switch their cell fates from differentiated to undifferentiated status under proper culture conditions,which is designated as totipotency.As a result,plant cells can easily regenerate new tissues or organs from a wide variety of explants.However,the mechanism by which plant cells have such remarkable regeneration ability is still largely unknown.In this study,we used a set of meristem-specific marker genes to analyze the pattes of stem cell difrerentiation in the processes of somatic embryogenesis as well as shoot or root organogenesis in vitro.Our studies fuish preliminary and important information on the pattes of the de novo stem cell difierentiation during various types of in vitro organogenesis.