Transcript Powerpoint

Unit 3
Lesson 5
Plant Hormones and Their Effects
8/3/2016
Unit 3, Lesson 5, Plant Hormones
and Their Effects
1
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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Unit 3, Lesson 5, Plant Hormones
and Their Effects
2
Types of Plant Hormones
• There are four common types of plant
hormones:
– Auxins
– Gibberellins
– Cytokinins
– Ethylene
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Unit 3, Lesson 5, Plant Hormones
and Their Effects
3
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
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Without
Auxins
Unit 3, Lesson 5, Plant Hormones
and Their Effects
4
Description of Gibberellins
• Gibberellins also
promote cell
elongation.
• Dwarf plants are often
“dwarfed” because
they cannot produce
gibberellins or can’t
process it.
• Fruit farmers use it to
enhance fruit
formation.
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Unit 3, Lesson 5, Plant Hormones
and Their Effects
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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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Unit 3, Lesson 5, Plant Hormones
and Their Effects
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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.
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Unit 3, Lesson 5, Plant Hormones
and Their Effects
7