““With his makeshift centrifuge, Knight had applied a force on the seedlings that mimicked gravitation and demonstrated that the roots always grew in the direction of this centrifugal force-while the shoots grew in the opposite direction. Knight's work provided the first experimental corroboration for Duhamel's observations. He showed that roots and shoots respond not only to natural gravity, as Duhamel showed, but also to an artificial gravitational force supplied by his waterwheel-powered centrifuge. But this still didn't explain how a plant could sense gravity.””
