Rapid plant movement is seen in many plants and there are different mechanisms based on the speed of the movement and the situation the plant is in. Some plants may make movements within 2 seconds while some may take 20 seconds to complete a motion. Additionally, for some plants the movement can involve action potentials being activated, or it can involve changes in water pressure and fluctuation of ions moving in and out of cells. In the case of the "Averrhoa carambola" plant it takes about 20 seconds for the leaves to move from their horizontal position to vertical. This mechanism involves the flux of ions and water. When the leaves receive an external stimulus (hands herbivores) this will translate to an electrical stimulus which then leads to the flow of ions (specifically the potassium and chloride) out of the pulvinus. Within the pulvinus, there are flexor and extensor cells, and this is where the change of potassium and chloride concentration occurs. So as you can see in the diagram, when the cell is in its turgid state, the leaves are horizontal, and cells are filled with water. So when the chloride and potassium move out of the cells, the water will flux out which results in the leaves facing vertically. This movement of the leaves drooping takes only a couple of seconds as we saw in the video. However, when the leaves or the tree is shaken, this will activate contractile proteins that are in the pulvinus, and they will cause the leaves to droop.