The detection of gravity plays a fundamental role during the growth and evolution of plants. Although progress has been made in our understanding of the molecular, cellular and physical mechanisms involved in the gravity detection, a coherent scenario consistent with all the observations is still lacking. In this special issue article, we discuss recent experiments showing that the response to inclination of shoots is independent of the gravity intensity, meaning that the gravity sensor detects an inclination and not a force. This result questions some of the commonly accepted hypotheses and leads to propose a new 'position sensor hypothesis'. The implications of this new scenario are discussed in light of the different observations available in the literature.

SummaryA fast and in vivo approach to assess the dynamics of root apical meristem length.

Analysis of the growth and orientation of roots of Arabidopsis mutants with differing root cap sizes and shapes indicates that the form of the cap affects root responses to variations in the strength of the growth medium.

HighlightMaximal axial pressures exerted by freely growing roots are restricted by root buckling but are increased when root lateral bracing is provided.