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Did you see that? That plant just moved. This is mimosa putica it's also called the sensitive
plant because it is sensitive to touch. If you brush up against it or shake the stem
it will respond by drooping and collapsing its leaves. Like its name implies, the plant
is very sensitive. It moves in response to rough handling or just a gentle touch, heat, water
loss, and even the time of day can make it fold its leaves. They will fold up at night
or even just if you move it into a dark room. The secret behind the sensitive plant's movement
is water pressure. Just like air pressing against the sides of a balloon keeps it inflated,
the water filling the plants' cells and tissues keeps it upright. While most plants will slowly
droop and wilt when they need water, the sensitive plant is able to swiftly collapse its leaves
by carefully controlling the flow of water into and out of its cells. At the base of
each leaflet you can sometimes see a pale dot. These dots are literally where the action
is. The cells here are equipped with special biochemical pumps that quickly move water
out of the cell causing the leaflet to collapse inward. Although the leaf can collapse quickly
the process of moving water back into the cell takes longer. It typically takes about
15-20 minutes for the leaf to return to its expanded position. It's similar to the way
you can quickly release pressure from a balloon but filling it up takes more time and effort.
Whatever the reason behind it, this ability makes the sensitive plant a lot of fun to
play with.