Throughout their life cycle, plants undergo a number of essential developmental transitions while they are exposed to constantly changing environments. As sessile organisms, plants have to ensure their survival through rapid adoption to these environmental changes. 

To understand these adaptation processes, we examine signal transduction pathways and transport mechanisms of the plant hormones auxin and gibberellins. In both processes, regulation via the ubiquitin-proteasome system is very important, a process that eukaryotes use to target proteins for degradation or to regulate the intracellular protein transport.