Abstract

Organogenesis in plants is closely related to the activity of the shoot apical meristem. The formation of lateral organs, such as leaves or flowers, is initiated at the meristem periphery by the establishment of local auxin maxima. In contrast to flowers, leaves are organs of dorsiventral symmetry, which is manifested in adaxial-abaxial leaf polarity. Adaxial and abaxial leaf sites are anatomically and functionally distinct, and their juxtaposition is essential for generating the flattened shape of a leaf blade. In this talk I will discuss how adaxial and abaxial cell fates are established at the shoot apical meristem of Arabidopsis, and what the role of auxin is in this process. Furthermore, I will show that that tracing cell lineages based on time-lapse imaging of a growing shoot apex is a useful toot that enables to link cell fates with dynamic gene expression patterns.