Unit 3 Lesson 5 Plant Hormones and Their Effects

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Unit 3Lesson 5Plant Hormones and Their Effects
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Functions of Plant Hormones

• Plant hormones are chemicals that are produced in
  one part of the plant and transported to another
  part, where it causes a physiological change.

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Types of Plant Hormones

• There are four common types of plant hormones
• Auxins
• Gibberellins
• Cytokinins
• Ethylene

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Description of Auxins
With Auxins

• Auxins promote cell elongation.
• It weakens the connections between the cellulose
  fibers in the cell wall, which allow them to
  stretch and grow longer.
• Auxins promote stem growth

Without Auxins
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Description of Gibberellins

• Gibberellins also promote cell elongation.
• Dwarf plants are often dwarfed because they
  cannot produce gibberellins or cant process it.
• Fruit farmers use it to enhance fruit formation.

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Description of Cytokinins

• Cytokinins stimulate cell division (cytokinesis).
  
• They produce more proteins by promoting mitosis.
• Cytokinins are produced in the roots.

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Description of Ethylene Gas

• Ethylene is a simple, gaseous compound composed
  of carbon and hydrogen that speeds the ripening
  of fruit.
• Ethylene causes the cell walls to become soft and
  causes the fruit to become sweet.