Plant Responses Flashcards
What is a tropism?
A plants response to external stimulus
What are the different tropisms
Phototropism (light)
Geotropism (gravity)
Thigmotropism (touch)
Hydrotropism (water)
Chemotropism (chemicals)
What is an auxin?
A growth regulator
Give the production site of an auxin
IAA is an auxin produced in the meristems of shoots
What is a growth inhibitor and an example
A chemical that causes a reduction in growth of plants e.g ethene
What us a growth promotor
Chemical that causes increased growth in plants
What are the effects of auxins
- Tropisms
- Apical dominance
- Root growth
- Fruit formation
Give some structural and chemical examples of plant defenses
Structural:
Thorns
Stinging cells
Guard cells
Thick cuticle
Chemical:
Toxic chemicals
Heat shock proteins - Protect enzymes
What are some uses of plant regulators in horticulture
- Rooting powders
- Synthetic auxin used as a weed killer
- Unrippened food sprayed with ethene
Describe the mechanism of phototropism
- Plant receives light from one side, auxin travels down dark side of the stem
- Auxin makes stem elongate faster
- Bends stem towards the light
