Hydrotropism

Definition - What does Hydrotropism mean?

In plant biology, hydrotropism is a plant’s growth response towards water sources. Hydrotropism, which is triggered by plant hormones, can be a positive or negative response, whereby the plant will either turn away from water concentrations, protecting itself from oversaturation, or move towards them, protecting itself in times of drought.

Consequently, through hydrotropism, the plant is able to avoid drought-related stress since the root cap can orientate itself towards moister parcels of land.

MaximumYield explains Hydrotropism

Plant hormones known as auxins play an important role in bending or orienting the roots towards water sources. These hormones have also been known to trigger a rapid growth spurt in one side of the root, hence enabling the plant to bend towards the water.

A plant’s ability to grow towards some kind of moisture gradient can protect the plant from various kinds of mineral deficiency. Studies have shown that hydrotropism can allow plants to grow in space, whereby the roots respond directly to environmental stimulation in spite of zero gravity. However, it has been noted that hydrotropism in micro or zero gravity causes the plants to grow sideways or latterly.

Hydrotropism is just one of many ways plants can move in response to their surroundings. Other ways plants move include:

  • Gravitropism and geotropism (movement relative to a gravitational field, or toward the center of the Earth)
  • Thigmotropism (plant growth in response to physical contact)
  • Chemotropism (movement in response to a chemical in the environment)
  • Phototropism (plant growth and movement in response to lighting levels)
  • Thermotropism (response dependent upon temperature)

Plant movement, including hydrotropism, has been fascinating researchers for decades.

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