Is carbon reserve storage an overflow of carbon?

It is generally assumed that C-storage in plants follows a strict source-sink-balance, where stores are enlarged at periods of low sink activities and cashed in situations of limited C-supply. In this session I will question this concept and introduce current experiments to test the indicative value of non-structural carbohydrate reserves for the C-supply status of plants. Based on these studies, I will discuss if genetic controls (e. g. phenological control of storage) or environmental stress (e.g. drought) can lead to C-storage against prevailing C-source limitation.