Leaflets of Mimosa pudica (common names: sensitive plant, touch-me-not) have a remarkable ability to close up in response to being touched or physically moved.
How fast can the leaflets close?
How does this occur?
And more importantly, what benefit could this unusual response provide to the plant?
If just the leaflets located toward the end of a leaf are touched, the adjacent leaflets close in fairly rapid succession until all leaflets on a leaf close up.
Explain how electrical signaling may be involved in this response.

In many species native to tropical wet forests, seeds do not undergo a period of dormancy. Instead, they germinate immediately. Predict the role of ABA in these seeds. How would you test your prediction?

Leaflets of Mimosa pudica (common names: sensitive plant, touch-me-not) have a remarkable ability to close up in response to being touched or physically moved.

How fast can the leaflets close?

How does this occur?

And more importantly, what benefit could this unusual response provide to the plant?

Researchers studied the rate of closing and reopening of leaflets by measuring changes in the distance between opposing leaflets after being touched. Their results are shown in the accompanying graph (d/dmax is actual leaflet distance relative to maximal leaflet distance).

How long does it take for leaflets to close?

How long to reopen?

Leaflets of Mimosa pudica (common names: sensitive plant, touch-me-not) have a remarkable ability to close up in response to being touched or physically moved.

How fast can the leaflets close?

How does this occur?

And more importantly, what benefit could this unusual response provide to the plant?

Which of the following terms best describes the leaflet movement?

a. Thigmonastic movements

b. Thigmotropism

c. Thigmomorphogenesis

d. Apical dominance

Leaflets of Mimosa pudica (common names: sensitive plant, touch-me-not) have a remarkable ability to close up in response to being touched or physically moved.

How fast can the leaflets close? How does this occur?

And more importantly, what benefit could this unusual response provide to the plant?

The mechanism of leaflet closure is similar to what happens during the shrinking of guard cells and closing of stomata (see Figure 37.22). When in the open position, special cells on the upper surface of Mimosa leaflets are filled with water and are under pressure.

Explain how osmosis and flow of ions into and out of these special cells may be involved in leaflet closure and reopening.

Leaflets of Mimosa pudica (common names: sensitive plant, touch-me-not) have a remarkable ability to close up in response to being touched or physically moved.

How fast can the leaflets close? How does this occur?

And more importantly, what benefit could this unusual response provide to the plant? Researchers have hypothesized that rapid leaf movements in Mimosa serve as a defense mechanism (e.g., closing leaflets may deter plant-eating insects).

Propose an experiment to test this hypothesis.

If apples are to be stored for long periods, it is best to keep them in a place with good air circulation. Explain why.

Leaflets of Mimosa pudica (common names: sensitive plant, touch-me-not) have a remarkable ability to close up in response to being touched or physically moved.

How fast can the leaflets close?

How does this occur?

And more importantly, what benefit could this unusual response provide to the plant?

Mimosa leaflets also close on their own at dusk and reopen at dawn (this cycle develops as a circadian rhythm).

What receptor molecule mentioned in this chapter is likely involved in regulating this process?