Chapter 25 Plant Responses and Adaptations Set Up

Chapter 25 Plant Responses and Adaptations.

Set Up Foldable • Fold Long and Skinny (hotdog) • Fold short and fat 2 times (hamburger) • Open so looks like below, crease is on top

What is a tropism? Tropism ~ a response of a plant to an environmental stimulus.

Tropism • Tropism is growth in response to an external stimulus (factor that elicits a response). • Positive tropism: Plant growth toward a stimulus (water, sunlight) • Negative tropism: Plant growth away from a stimulus (spilled gas, toxins, too much sun or not enough)

What is phototropism? Phototropism ~ a tendency of plants to grow toward a source of light.

Phototropism • Phototropism is a change in the growth of a plant in response to light. • The stalk displays positive phototropism growing towards the light.

What is gravitropism? Gravitropism ~ a tendency of a plant to grow in a direction in response to the force of gravity.

What is thigmotropism? Thigmotropism ~ the response of plants to touch.

Geotropism (Gravitropism) • Geotropism is a change in the growth of a plant in response to gravity. • The stalk displays a negative geotropism growing away from gravity. • The roots display a positive geotropism growing towards gravity.

Hydrotropism • Hydrotropism is a change in the growth of a plant in response to water. • The roots display a positive hydrotropism growing towards water.

Turgor Pressure • http: //www. kscience. co. uk/animations/turgor. htm • Click on link above for example

The cell’s vacuole does not have any water in it. The cell is flaccid. The vacuole does not have a lot of water in it. The vacuole and cell wall push against each other. The vacuole is now full of water.