Summary
Tropic responses are how plants grow towards or away from stimuli like light and gravity. Phototropism — growth response to light. Example: Shoots growing towards light show positive phototropism. Gravitropism — growth response to gravity. Example: Roots growing downwards show positive gravitropism. Auxin — a plant hormone that regulates growth by elongating cells. Example: Auxin accumulates on the shaded side of a plant, causing it to bend towards the light.
Exam Tips
Key Definitions to Remember
- Phototropism: Growth response to light.
- Gravitropism: Growth response to gravity.
- Auxin: Plant hormone that controls growth.
Common Confusions
- Confusing positive and negative tropic responses.
- Misunderstanding how auxin affects shoots and roots differently.
Typical Exam Questions
- What is phototropism? Growth response of plants towards light.
- How does auxin affect root growth? Auxin inhibits cell elongation in roots, causing them to grow downwards.
- Why do shoots bend towards light? Auxin accumulates on the shaded side, causing faster growth there.
What Examiners Usually Test
- Understanding of how auxin affects plant growth.
- Differences between positive and negative tropic responses.
- Application of tropic responses in real-life scenarios like agriculture.