Because the leaves and petioles of mimosa have special structures. There is a large vascular bundle in the center of occipital lobe, which is surrounded by parenchyma and has many intercellular spaces.

When the vibration is transmitted to the occipital lobe, the cellular fluid in the parenchyma cells in the upper part of the occipital lobe is discharged into the intercellular space, which reduces the swelling pressure of the cells in the upper part of the occipital lobe, while the original swelling pressure is maintained in the lower intercellular space. As a result, the leaflets stand upright, the two leaflets are close together, and even the whole leaf hangs down.

Mimosa is a perennial herb or subshrub of Leguminosae. Because its leaves respond to heat and light, they will close immediately when touched by external force, so it is named mimosa. Shaped like a fluff ball. After flowering, it bears pods and the fruit is oblate. The leaves are feather-like compound leaves, alternating with each other and arranged in a palm shape.

Extended data:

This special skill of mimosa has its historical roots. Its hometown is Brazil in tropical South America, where there are often strong winds and heavy rains. Whenever the first drop of rain hits the leaves, it immediately closes the leaves and hangs down the petiole to avoid the damage of the storm. This is an adaptation to changes in external environmental conditions.

In addition, the movement of mimosa can also be regarded as a way of self-defense. When the animal touched it lightly, it closed the leaves, and the animal dared not eat any more.

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