Homeostats - the hidden rulers of ion homeostasis in plants
Ion homeostasis is a crucial process in plants that is closely linked to the efficiency of nutrient uptake, stress tolerance and overall plant growth and development. Nevertheless, our understanding of the fundamental processes of ion homeostasis is still incomplete and highly fragmented. Especially at the mechanistic level, we are still in the process of dissecting physiological systems to analyze the different parts in isolation. However, modeling approaches have shown that it is not individual transporters but rather transporter networks (homeostats) that control membrane transport and associated homeostatic processes in plant cells. To facilitate access to such theoretical approaches, the modeling of the potassium homeostat is explained here in detail to serve as a blueprint for other homeostats. Based on a few, elementary knowledge about the thermodynamics of the different transport processes, it is possible to draw fundamental conclusions about the properties and physiology of the transporter network.