Root photomorphogenesis in laboratory-maintained Arabidopsis seedlings.

In nature, root systems of most terrestrial plants are underground in darkness. Nevertheless, several photoreceptors have been found in roots and light-responsive mechanisms allowing roots to escape from strong light conditions have been discovered. In transparent Petri dishes, regular light exposure affects root morphology and behavior. We advocate the use of darkened Petri dishes to allow roots to be kept in darkness, thus mimicking more closely the conditions in nature.