Plants acquired multicellularity independently of animals and have evolved unique mechanisms to construct body structures adapted to a sessile lifestyle. Key insights into plant body building may lie in several characteristic features, including the flexibility of cell differentiation and proliferation, autonomous pattern formation, multilayered intercellular interactions, plant-specific programmed cell death, distinctive gene regulatory networks, and the formation of plant-characteristic tissues and organs based on these properties. To study the molecular mechanisms of these processes, we have utilized various bioresources and experimental systems, including Arabidopsis mutants and cell and tissue cultures. Combining these tools with approaches from molecular genetics, physiology, biochemistry, developmental biology, and CLSM imaging, we seek to clarify the fundamental principles underlying plant body construction.