Organization and patterning of the leaf venation network in flowering plants varies greatly between species. In particular, unlike the diverse reticulated vein networks that develop in the variably shaped leaves of eudicotyledonous plant species, monocotyledonous grass leaves are unified by a linear shape and a pattern of striated longitudinal veins that extend from base to tip. However, differences exist between monocot species in the number and type of veins that develop across the leaf. Notably, some features of the venation pattern are closely related to the type of photosynthesis performed by the plant.
The process that patterns veins relies on molecular and cellular events being co-ordinated in both space and time. Because of the shape (curled around the stem) and position (wrapped inside the older leaves) of monocot leaf primordia, the underlying mechanisms are difficult to dissect and poorly understood. We developed a 3D imaging method which allowed us to study the spatiotemporal complexity of venation patterning at the organ scale in monocots. Using this method, we conducted a kinetic analysis of vein formation during leaf growth in C3 and C4 photosynthesising model grass species.
Development of the leaf venation network requires the specification of procambial cells within the ground meristem of the primordium and subsequent proliferation and differentiation of the procambial lineage to form vascular strands. By following cell divisions during early leaf growth, we investigated how growth in the leaf influences the parallel venation patterns observed in both C3 and C4 species. Together our approaches revealed distinct relationships between cell divisions and venation patterning in C3 vs C4 grasses.
As a newcomer, I will also take this opportunity to briefly present my background and the research project I am currently developing within the CERES team.
