Figure 5.

A bistable model of the Venus flytrap opening/closing mechanism. The model is constructed based on water kinetics between the outer and inner layers of the lobes. Water supply is distributed to both layers depending on the layer volume, while water is consumed by transpiration and chemical reactions. Voltage-gated channels block water flow to the inner layer by maintaining a H⁺ gradient, which leads to high elastic energy in the open state of the trap. In an energy consuming step, the AP triggers an ATP-dependant H⁺ pump that rapidly pumps H⁺ against the gradient. APs open the voltage gated channels for a short time, water rushes into the inner layer, and the trap relaxes to semi-closed state. More APs can open the voltage gated channels again, and push a small amount of water to the inner layer. The reopening signal can transport the water back to the outer layer.