The Untouchable: An Adaptive Spring-Model Buckling for the Mimosa Pudica Stimuli Response

Mimosa Pudica (MP) possess a hierarchical leaf-folding behavior in response to external disturbances [1]. As observed in other plants [2], such fast movements are mechanically achieved by osmotic regulation of tissue pressure in specific apparatus, pulvini in the case of the MP. Depending on the intensity and location of the stimuli, the triggered kinematics can involve a pair of leaves up to the collapse of the entire branch. Because of this progressive on-off behavior, we modeled the folding system as the linear buckling of a concentrated linear elasticity system, realized by rotational springs and considering a simple time function for the electrochemical signaling. We then described the leaves stimuli adaptive functioning by a modal tuning of the spring stiffnesses. Finally, we proposed a tuned buckling loads to train a neural network to describe a learning model [3] for the equilibrium related MP intelligence and morphological features.