Abstract Background and Aims Mimosa pudica closes its leaves rapidly after stimulation but recovers on a much slower timescale. The biophysical mechanisms that govern this slow recovery remain unclear. Methods A transient two-dimensional bio-chemo-electro-mechanical model of the main pulvinus is developed based on mass and momentum conservation, poroelasticity, and a representative volume element description. Water potential, membrane water channels, and ionic pumps are represented explicitly to drive reversible turgor regulation. The model includes vascular tissue anatomy, a cell volume dependent mechanical relation that links hydrostatic pressure to turgor, and diffusive transport of water and multiple ionic species. Key Results Comparisons with published data indicate that the model captures ionic concentration transients, petiole bending, pulvinus deformation, and turgor evolution during slow recovery. Parameter studies of the water diffusion coefficient, pore surface fraction, and cell volumetric modulus identify key determinants of recovery speed and deformation amplitude. Conclusions The slow recovery of Mimosa pudica is governed by a coupled regulatory process in which membrane mediated transport drives reversible turgor changes and concurrent variations in effective tissue stiffness, yielding a closed-loop recovery response.
Zeng et al. (Thu,) studied this question.