Study Notes
Plant hormones are chemicals that regulate plant growth and responses to stimuli such as light and gravity. Auxin — a growth hormone that controls the direction of growth in plants. Example: Auxin causes plant shoots to grow towards light by accumulating on the shaded side, causing cells to elongate. Geotropism — a plant's growth response to gravity. Example: Roots exhibit positive geotropism by growing downwards, while shoots show negative geotropism by growing upwards. Phototropism — a plant's growth response to light. Example: Shoots grow towards light to maximize photosynthesis.
Exam Tips
Key Definitions to Remember
- Auxin
- Geotropism
- Phototropism
Common Confusions
- Mixing up geotropism and phototropism
- Understanding how auxin affects roots and shoots differently
Typical Exam Questions
- What is the role of auxin in plant growth? Auxin regulates the direction of growth by causing cell elongation.
- How do plants respond to light? Plants grow towards light due to phototropism, regulated by auxin.
- What is geotropism? Geotropism is a plant's growth response to gravity.
What Examiners Usually Test
- Understanding of how auxin affects plant growth
- Differences between geotropism and phototropism
- Practical applications of plant hormones in agriculture