How cellular events are coordinated across scales to generate organ shape and pattern remains a central question in plant development. In this talk, I will present two examples illustrating how differential growth, geometry, and mechanical forces contribute to plant morphogenesis.
First, I will focus on leaf margin patterning in Arabidopsis thaliana. Using 3D and time-lapse imaging of developing leaves, we map cell division and growth during serration formation. We show that the boundary-associated transcription factor CUC3 acts as a local negative regulator of cell growth, and that its dynamic expression in a small number of margin cells drives the differential growth underlying leaf serrations.
Second, I will present recent results on the long-standing observation that the final division of the stomatal lineage aligns with the main axis of the leaf. Using an artificial system in which all epidermal cells adopt stomatal fate, combined with live imaging, modeling, and mechanical perturbations, we show that in certain contexts this division aligns with the organ axis and tensile stress rather than with cell geometry alone.
