Plants have the amazing capacity to adapt their growth and development to an everchanging environment. This can be achieved by local changes in levels of growth regulating plant hormones. One of these plant hormones is auxin. It regulates the number and shape of organs, such as leaves, roots and flowers, but is also involved in achieving vertical growth and bending towards the light. Each of these processes is the result of a local accumulation of auxin in specific cells. An important mechanism controlling local auxin content is directional auxin transport from cell to cell, mediated via auxin-transporting PIN proteins. Typically, these proteins localise to one side of a cell and pump auxin out of the cell in that direction. Interestingly, cells coordinate their PIN localisations with that of neighboring cells, thereby delineating a path of auxin transport possibly via a self-regulating effect of auxin on PIN trafficking that controls the PIN levels in the membrane. In the following years I plan to study the involvement of the signaling molecule Ca2+ in the mechanism of auxin-regulated PIN trafficking. To achieve this, accurate measurements of the behaviour of Ca2+ in response to various treatments will be of fundamental importance to understand how auxin controls Ca2+ levels. Therefore, I plan to acquire an automated system (Port-a-Patch, Nanion) to gain rapid, accurate, high quality electrophysiological data on auxin-induced Ca2+ currents in Arabidopsis root cells.