A. Bérut, H. Chauvet, V. Legué, B. Moulia, O. Pouliquen, Y. Forterre "Gravisensors in plant cells behave like an active granular liquid" PNAS 115, 5123-5128 (2018)


The sensor of gravity in plants consists of tiny starch-rich grains called statoliths that sediment and form miniature granular piles at the bottom of the gravisensing cells. How such a sensor could be a reliable clinometer is unclear, as granular materials are known to display jamming and finite avalanche angles. Here we address this issue by comparing statolith avalanches in plant cells to microfluidic avalanches of Brownian particles in biomimetic cells. We reveal that statoliths behave like a liquid, not a granular material, due to the cell activity that strongly agitates statoliths. Our study elucidates the physical grounds of the high sensitivity of plants to gravity and bridges the active microrheology of statoliths to the macroscopic response of the plant.

Bérut et al, Proc. Natl. Acad. Sci. USA 115, 5123-5128 (2018)


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