Module 5.5 Part 5 (Plants)
- Created by: RebeccaSmithySmith
- Created on: 17-12-18 17:38
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- Module 5.5 Plant and Animal Responses (part 5)
- Plant stimuli
- no sensory organs
- Abiotic = non-living stimuli
- Biotic = living parts of the nevironment
- Tropism (growth response to a stimuli)
- Phototropism = light
- Geotropism = gravity
- shoots have negative geotropism (grown upwards)
- Hydrotropism = moisture
- Thigmotropism = touch
- Chemotropism = chemicals
- Nastic movement
- touch sensitive leaves
- leaves fold rapidly in
- caused by rapid uptake of water at the base of each leaflet, adjacent cells lose water and collapse
- cannot be classed as a tropism
- non-directional responses aka ' nastic movement
- caused by bio-electrical signals
- Responses to Herbivory
- Tannins
- water soluble flavonoids
- stored in vacuole and faital to insects
- bitter taste to herbivores
- Alkalolds
- Nitrogenous compounds from amino acids
- bitter taste or toxic
- e.g. caffeine or nicotine
- capsaicin in chillies
- Pheromones
- chemical released by a species to affect another organism in the same species
- ethene released by plants causes ripening of fruit in nearby plants/leaves
- oxides of ethene are toxic to insects
- controls chemical defenses
- Tannins
- Plant stimuli
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