On the front row: Sporophyte development in the fern Ceratopteris richardii

Ferns have an unique lifestyle compared to other plants, allowing us to better understand what processes are necessary to build a plant. Fern lifecycles alternate between a very simple 2D plantlet and much more complex 3D growth patterns. In this thesis, I tried to better understand which processes steer the development of these complex 3D growth patterns. By comparing the two growth forms, we see that specific developmental hormones probably underly this process. We could even induce the 3D growth form by altering hormone levels. Lastly, we focused on embryo development as this series of cell divisions start the process of 3D growth. From a single cell, a complete new and complex 3D organisms develops. Surprisingly, we could see that the orientation of these embryos depends on the maternal tissue surrounding the embryo, suggesting that embryonic division are somehow regulated by tissue mechanics. Together, we identified processes that underly the 3D development of ferns specifically, but also plants in general.