PHOTOTROPISM Meaning and
Definition
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Phototropism is a biological phenomenon observed in plants and some organisms that involves the directed growth or movement of an organism in response to light. It refers specifically to the process by which plants respond to light by bending or orienting themselves towards or away from its source to maximize their exposure to or minimize their exposure to light.
The process of phototropism is typically controlled by a plant hormone called auxin, which is produced in the tips of plant stems and transported downward. When a plant is exposed to light, the light-sensitive pigments within its cells, known as photoreceptors, perceive the light and trigger a series of physiological and biochemical changes. These changes include the redistribution of auxin within the plant, leading to a higher concentration of auxin on the shaded side of the stem. As a result, the cells on the shaded side elongate, causing the stem to bend towards the light source.
Phototropism is an essential adaptive mechanism for plants as it enables them to optimize their photosynthesis process by ensuring that their leaves and stems receive an adequate amount of sunlight. This phenomenon can be observed in various plant structures, including leaves, stems, and even tendrils. For example, climbers such as vines exhibit positive phototropism, where they grow towards light sources to aid their support and access sunlight for photosynthesis.
Overall, phototropism allows plants to react and adapt to their light environment, maximizing their energy acquisition and ultimately influencing their growth and survival.
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A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
Common Misspellings for PHOTOTROPISM
Etymology of PHOTOTROPISM
The word "phototropism" is derived from the combination of two Greek words: "photo" meaning light and "tropism" meaning turning or movement.
- "Photo" (φωτός) comes from the Greek word "phos" (φως), which means light.
- "Tropism" (τρόπος) is derived from the Greek word "tropos" (τρόπος), meaning turning or direction.
When combined, "phototropism" literally translates to "light turning" or "movement due to light". It is a biological term used to describe the growth or movement of an organism towards or away from light stimulus.
