Abstract
In higher plants, leaves are formed from the shoot apical meristem (SAM). However, some species in Streptocarpus (Gesneriaceae) do not retain SAM, while leaves are formed via rosette leaves from a kind of intercalary meristem named groove meristem. Thus, the process of leaf formation is intriguing from the viewpoints of developmental biology. In this study, we used Streptocarpus parviflorus, a rosulate species and followed the process of the first leaf formation. It was formed in the axil of the macrocotyledon. When the leaf formation was classified into two stages, leaf primordium was first bulged, while lamina and petiolode were differentiated in the second stage. Notably, tunica-corpus-like structure was observed at the bulged structure. We have particularly interested in examining the origins of respective organs with the detection of BrdU incorporation. The significance of such temporal and spatial changes of cell division activity was discussed.
