gravitropism

Examples of gravitropism in the following topics:

• Plant Responses to Gravity

  • Gravitropism ensures that roots grow into the soil and that shoots grow toward sunlight.
  • Growth of the shoot apical tip upward is called negative gravitropism, whereas growth of the roots downward is called positive gravitropism.
  • The mechanism that mediates gravitropism is reasonably well understood.
  • Other hypotheses, which involve the entire cell in the gravitropism effect, have been proposed to explain why some mutants that lack amyloplasts may still exhibit a weak gravitropic response.
  • The roots grown downward in the direction of gravity, which is positive gravitropism, and the shoot grows upward away from gravity, which is negative gravitropism.

• Auxins, Cytokinins, and Gibberellins

  • The term auxin is derived from the Greek word auxein, which means "to grow. " Auxins are the main hormones responsible for cell elongation in phototropism and gravitropism.

• Abscisic Acid, Ethylene, and Nontraditional Hormones

  • Apical dominance, seed germination, gravitropism, and resistance to freezing are all positively influenced by hormones.