One strange plant that is native to Central and South America is extremely sensitive, so sensitive that it will only take a little touch or even a scream for it to wilt up and practically die. Imagine that you are trying to grow your herb garden but every time you make a loud noise your plant simply dies!
Part of the Fabaceae pea family this perennial herb is extremely odd as its leaves will close inwards whenever it feels threatened. You can touch one leaf and the whole plant will recoil in shock, effectively going to sleep. It is very usual to see kids playing with these plants around South America, fascinated by how the plant seems to close up & shrink all on its own.
They even close up completely if you just blow a little air at them or give the Mimosa Pudica a little shake, in fact, many people call it the Mimosa sensitive plant and have nicknamed it the Touch Me Not plant. As a child seeing this happen may look like a great mystery or even magic, but there is actually a biological reason that it happens.
The movement of the plant happens due to a phenomenon is known as Thigmonasty. Water inside the plant cells apply pressure on the walls of the plant, which is called turgor pressure & this causes the plant to curl up. Now the reason the leaves close up is that it feels threatened by an external force, so the plant releases some chemicals it releases so much that the body of the plant collapses on itself, causing the leaves to curl up.
No one really knows why it does this, botanists are confused as the mechanism will cause problems with the photosynthesis process (the process that allows plants to live from sunlight). But the only explanation that makes sense is it must have been a defense mechanism, possibly against insects or some other animal that loved to snack on mimosa leaves.