Chemotropism

Definition - What does Chemotropism mean?

In plant biology, any type of 'tropism' is a plant's physical response to some sort of external stimuli. The response is typically movement of some sort.

Chemotropism is a form of tropism whereby the plant’s organism grows in response to a chemical stimulus. According to botanists, plants can display both negative and positive chemotropisms.

In fact, studies have shown that some plants tend to turn away from poor-quality soil and face better growing conditions instead, suggesting a form of chemical sensing in the root and stem system.

MaximumYield explains Chemotropism

Because of chemotropism, some plant roots develop an increased sensitivity to potential attackers such as fungi or bacteria. Similarly, these plants have a heightened awareness of nutrient sources and automatically proliferate in areas with a high concentration of iron.

Additionally, some studies have shown that pollen can also respond to chemical stimulation, whereby the pollen tube starts to learn towards external stimuli.

According to botanists, plants also move in the following main ways:

  • Hydrotropism (growth or developmental response to water)
  • Thermotropism (response dependent upon temperature)
  • Phototropism (movement toward light)
  • Gravitropism and geotropism (movement relative to a gravitational field, or toward the center of the Earth)
  • Thigmotropism (plant growth in response to physical contact)
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