Nanomechanics and plant growth

Establish a link between root plant growth and cell surface elasticity

Plant growth is extremely sensitive to environmental stresses, which ultimately act on the functioning of cell walls ; the relaxation or blocking of the walls allows, respectively, cell growth or its arrest. In the model plant Arabidopsis growing in vitro, we have shown that stress due to a deficiency in the nutrient phosphate "-Pi" blocks root growth very quickly and irreversibly (figure below).

If chemical bonds are responsible for stopping cell expansion, then they should rapidly modify the mechanical properties of the walls. To test this hypothesis, we used atomic force microscopy (AFM). We demonstrated an increase in cell wall stiffness in the absence of Pi in the root transition zone by nanoindentation measurements with AFM. 

Finally, these results demonstrate that AFM is an excellent technique allowing a precise measurement of a rapid change in the plant root state in a living organism.

AFM measurements were performed by Christian Godon and curve analyses were performed by Jean-Marie Teulon on seedlings produced by Christian and whose seeds were provided by Thierry Desnos.

Balzergue C, Dartevelle T, Godon C, Laugier E, Meisrimler C, Teulon J-M, Creff A, Bissler M, Brouchoud C, Hagège A, Müller J, Chiarenza S, Javot H, Becuwe-Linka N, David P, Péret B, Delannoy E, Thibaud M-C, Armengaud J, Abel S, Pellequer J-L, Nussaume L and Desnos T (2017) Low phosphate activates STOP1-ALMT1 to rapidly inhibit root cell elongation. Nat. Commun. 8 : 15300.