Problem : What are the two ways in which plants can move in response to stimuli?

Plants can move toward or away from stimuli either by differential cell growth (tropisms) or by changes in turgor pressure (turgor movements).

Problem : List the three types of tropisms and what they respond to.

Phototropism (light), thigmotropism (touch), and gravitotropism (gravity).

Problem : Give two examples of how plants might exhibit thigmotropism.

Tree trunks grow thicker when exposed to strong winds and vines tend to grow straight until they encounter a substrate to wrap around.

Problem : Which kind of plant movement is easily reversible, tropisms or turgor movements?

Turgor movements.

Problem : What is turgor pressure? What causes it to change?

Turgor pressure is the force exerted by water inside the cell on the cell walls. Changing amounts of water within the cell cause the turgor pressure to change.