Hormones in plants
Plants respond to Something that sets off a reaction in the nervous system, for example, light, heat, sound, gravity, smell, taste, or temperature. These changes in the environment are detected by receptors in an organism. The plural is stimuli. slowly:
- Roots grow towards water.
- Shoots grow away from gravity.
- Shoots grow towards light – The response of a plant to light..
Phototropism
- Plant responds to unidirectional light (e.g. plant on a windowsill)
- Plant shoot bends towards light.
- Advantage of this response: - more light - moreChemical reaction that happens in plant cells. It converts carbon dioxide and water into glucose and oxygen in the presence of light. The glucose can then be used for a number of processes including growth. - more growth
How does a shoot bend towards unidirectional light?
- The shoot tip is sensitive to light and produces Plant hormones that control cell elongation. – if the tip is covered phototropism doesn’t occur.
- Light causes the uneven distribution of auxin – it moves downwards and accumulates on the shaded side.
- Auxin causes cells on shaded side to elongate faster than on the illuminated side – this is known as differential growth.
- The stem bends towards light.
