title: Inclination not force is sensed by plants during shoot gravitropism.
abstract: Gravity perception plays a key role in how plants develop and adapt to environmental changes. However, more than a century after the pioneering work of Darwin, little is known on the sensing mechanism. Using a centrifugal device combined with growth kinematics imaging, we show that shoot gravitropic responses to steady levels of gravity in four representative angiosperm species is independent of gravity intensity. All gravitropic responses tested are dependent only on the angle of inclination from the direction of gravity. We thus demonstrate that shoot gravitropism is stimulated by sensing inclination not gravitational force or acceleration as previously believed. This contrasts with the otolith system in the internal ear of vertebrates and explains the robustness of the control of growth direction by plants despite perturbations like wind shaking. Our results will help retarget the search for the molecular mechanism linking shifting statoliths to signal transduction.
authors.affiliation: Aix-Marseille Univ., CNRS, IUSTI UMR 7343, 13453 Marseille Cedex 13, France.|Integrative Physics and Physiology of Trees (PIAF), INRA, Univ. Clermont-Auvergne, 63000 Clermont-Ferrand, France.
authors.forename: Hugo
authors.initials: H
authors.lastname: Chauvet
authors.affiliation: Aix-Marseille Univ., CNRS, IUSTI UMR 7343, 13453 Marseille Cedex 13, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Pouliquen
authors.affiliation: Aix-Marseille Univ., CNRS, IUSTI UMR 7343, 13453 Marseille Cedex 13, France.
authors.forename: Yoël
authors.initials: Y
authors.lastname: Forterre
authors.affiliation: Integrative Physics and Physiology of Trees (PIAF), INRA, Univ. Clermont-Auvergne, 63000 Clermont-Ferrand, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Legué
authors.affiliation: Integrative Physics and Physiology of Trees (PIAF), INRA, Univ. Clermont-Auvergne, 63000 Clermont-Ferrand, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Moulia
mesh_terms: D018522:Gravitropism; D018520:Plant Shoots / Q000502:physiology*; D014908:Triticum / Q000502:physiology