Growth conditions modulate root-wave phenotypes in Arabidopsis

The cause for the wave-like growth of Arabidopsis thaliana roots on semi-solid medium remains unclear. Researchers have hypothesized a gravity-induced touch-response, circumnutation, or combinations thereof act as the major stimuli. Our data demonstrate that the gaseous environment within the Petri dish can override gravitational effects. Furthermore, we show that medium ion concentrations and gelling polymers modify the wave response. Although the mechanisms driving our wide-ranging wild-type phenotypes are currently unknown, these results are of immediate significance for interpreting genetic and physiological modifications of environmentally and genetically induced characteristics.