Plant mecano-perception and long-distance signaling: role of hydraulic signals

It is now well accepted that plants can detect mechanical stimuli such as wind or touch and respond to these stimuli by modifying their development and growth – a process called thigmo-morphogenesis (Jaffe et al 2002, Braam 2004, Telewski 2006). A fascinating feature of this mechanical-induced-growth response is that it is not only local, but also non-local: bending locally a stem or a branch can induce a very rapid (~ min) modification of the growth far away from the stimulated area (Coutand et al 2000, Pruyn et al 2000). The origin and nature of this signal is still not understood and remains a scientific barrier for the understanding of the growth modulation in plants. In this project, we address the possibility that long-signalling in plants could occur via the propagation of hydraulic signals. These pulse originate from a coupling between the local deformation of the tissues and the water pressure in the vascular system of the plant (Lopez et al 2014). We combine experiments on biomimetic poroelastic branches and real plants to answer the following questions:

- How hydraulic signals can be generated through mechanical deformation (bending of plant stems and branches)?

- What parameters control their physical properties and how they vary across the plant taxa (trees, non-woody plants)?

- What is the physiological role of these hydraulic signals on the long-distance perception of mechanical stimuli?