Inclination, not force, is detected in shoot gravitropism

Plant cells detect gravity as a consequence of the movement of dense starch granules called statoliths when the statoctyte, the cell that encompasses, them reorients. An open question has been whether the position of the statoliths within the statocyte or the force exerted by them is the primary gravisensing signal. Chauvet et al. designed an experiment to compare the growth (curvature) response of wheat coleoptiles to varying gravitational forces, and found that growth is sensitive to tip angle but independent of gravitational force. They interpret their results as support for the model that statocytes act as position sensors, not force sensors. Scientific Reports 10.1038/srep35431