When I posted about Tickle Me Plant, I was fascinated by its use in other country. I will never look again in that plant the same way. But of course, as a kid, Makahiya plants has been very fun.I just did not thought that it would be marketed as a toy.
The plant’s scientific name is Mimosa pudica. This is an annual or perennial herb and is native to South America and Central America (but can be found in most Asian countries too and is considered a weed). Below is an explanation (from wikipedia) on why the plant movies or folds inward when it is stimulated.
The leaves also close under various other stimuli, such as touching, warming, blowing, or shaking. These types of movements have been termed seismonastic movements. The movement occurs when specific regions of cells lose turgor pressure, which is the force that is applied onto the cell wall by water within the cell vacuoles and other cell contents. When the plant is disturbed, specific regions on the stems are stimulated to release chemicals which force water out of the cell vacuoles and the water diffuses out of the cells, producing a loss of cell pressure and cell collapse; this differential turgidity between different regions of cells results in the closing of the leaflets and the collapse of the leaf petiole. This characteristic is quite common within the Mimosoideae subfamily of the legume family, Fabaceae. The stimulus can also be transmitted to neighboring leaves. It is not known exactly why Mimosa pudica evolved this trait, but many scientists think that the plant uses its ability to shrink as a defense from predators. Animals may be afraid of a fast moving plant and would rather eat a less active one. Another possible explanation is that the sudden movement dislodges harmful insects.
Well, if you are as small as Makahiya, I guess its being “shy” saves them a lot from being eaten by animals. And if you have not noticed, most Makahiya plants have thorns in their stems.