Hydrotropism
Hydrotropism (pronounced: hy-dro-tro-pism) is a biological phenomenon observed in plants. It refers to the growth or movement of an organism, especially a plant, in response to water. The term is derived from the Greek words 'hydro' meaning water, and 'tropism' meaning a turning.
Etymology
The term 'Hydrotropism' is derived from two Greek words: 'Hydro' which means water, and 'tropism' which means turning. The term was first used in the late 19th century to describe the phenomenon observed in plants where their roots grow towards a water source.
Mechanism
The mechanism of hydrotropism involves the perception of a moisture gradient by the root cap. This perception triggers a signal transduction pathway leading to differential cell elongation and root curvature. The exact molecular mechanisms are still under investigation, but it is known that auxin, a plant hormone, plays a crucial role in this process.
Types of Hydrotropism
There are two types of hydrotropism: positive and negative. In positive hydrotropism, the plant's roots grow towards the water source. This is commonly observed in most plants. In negative hydrotropism, the plant's roots grow away from the water source. This is less common and is usually observed in plants that are adapted to dry conditions.
Related Terms
- Tropism: A general term for the directional growth responses of plants.
- Phototropism: The growth of a plant in response to light.
- Geotropism: The growth of a plant in response to gravity.
- Thigmotropism: The growth of a plant in response to touch or physical contact.
- Chemotropism: The growth of a plant in response to chemicals.
See Also
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