ClearDepth: a simple, robust, and low-cost method to assess root depth in soil.

Root depth is a major determinant of plant performance during drought and a key trait for strategies to improve soil carbon sequestration to mitigate climate change. While the model Arabidopsis thaliana offers numerous advantages for studies of root system architecture and root depth, its small and fragile roots severely limit the use of the methods and techniques currently available for such studies in soils. To overcome this, we have developed ClearDepth, a conceptually simple, non-destructive, sensitive, and low-cost method to estimate the root depth of Arabidopsis in relatively small pots that are amenable to mid- and large-scale studies.