BRAINCAKEGeotropism
Plants respond to gravity by directional growth called geotropism (also called gravitropism). Shoots are negatively geotropic and grow upwards, away from gravity. Roots are positively geotropic and grow downwards, towards gravity.
This means roots grow down into the soil, where they anchor the plant and absorb water and mineral ions, while shoots grow up towards the light needed for photosynthesis.
The response is controlled by auxins such as indoleacetic acid (IAA). When a plant is placed on its side, IAA accumulates on the lower side of both the shoot and the root.
Sign in free to see the rest of this lesson, the R.E.C.I.P.E. recall steps and the quiz
BrainCake is free. Make an account in seconds and pick up where this page stops.
More in Plant Responses
- Pheromones
- Response to Touch
- Tropisms
- Growing in the Dark
- Fruit Ripening
- Rooting Powder
- Hormonal Weedkillers
- Other Uses of Plant Hormones
All 19 lessons in Plant Responses · All AQA A-level Biology topics