Why does the mimosa close when touched? Does the mimosa close at night?

1. The reason why Mimosa closes when touched

Mimosa closes when touched, not because it is really shy; it is just a figurative metaphor. In fact, closing its leaves when stimulated by external stimuli is a way of self-protection. Because the growing environment in its place of origin is very harsh, it can only protect itself in this way. So how does the mimosa protect itself? The secret lies mainly in its petiole.

There is a special organ called "pulvinus" on the petiole of mimosa, in which grow many thin-walled cells. These cells are very sensitive and will begin to close as soon as they are slightly stimulated by external vibration or touch.

Then there is the physiological reaction of the mimosa itself. When its leaves are touched, the cell sap contained in the parenchyma cells in the pulvinus will flow to other places, reducing cell swelling. In this way, the pressure on the parenchyma cells will decrease, resulting in the leaves closing tightly and the petioles drooping.

In addition, when the external light is relatively weak, the water in the mimosa pulvinus that supports the leaves to unfold will flow to the gaps on both sides after being affected by external forces, which will also cause the leaves to close. But this phenomenon will not last long and will recover in about two minutes.

2. Will the mimosa close at night?

The leaves of mimosa close at night. Because there is no light at night, mimosa needs the right temperature to open its leaves and carry out photosynthesis under the sunlight. However, the temperature is relatively low at night and photosynthesis cannot be carried out. In order to keep warm, the leaves of mimosa will close at night.