How does Mimosa pudica defend itself from predators

Mimosa pudica has two primary defense mechanisms, one mechanical and one chemical.

1. Rapid Leaf Movement (Thigmonasty/Seismonasty): This is its most famous defense.
   • How it works: At the base of each leaf and leaflet is a swollen, joint-like structure called a pulvinus (plural: pulvini). These pulvini are filled with water-filled cells. When the leaf is touched, shaken, or rapidly heated, it triggers an electrical signal. This signal causes specialized "motor cells" within the pulvini to rapidly lose potassium ions.This, in turn, forces water out of the cells, causing them to lose turgor pressure and collapse.
   • Why it works: This sudden "wilting" and "drooping" motion serves several purposes:
     • Startles Herbivores: The rapid movement can scare away small insects.
     • Appears Less Appetizing: A shrunken, wilted plant looks less nutritious and appealing to a larger grazing animal.
     • Exposes Thorns: As the leaves fold up, they expose the sharp, prickly thorns on the plant's stem, making it a much more painful snack.
2. Chemical Defense (Thorns): The stems of the plant are covered in sharp, recurved prickles (thorns).These create a painful physical barrier that deters most animals from trying to eat the plant.

The plant also has a "chemical defense" in the form of mimosine, a toxic non-protein amino acid.While not its primary defense, mimosine can be poisonous to ruminant grazers if consumed in large quantities.