Page 132 - Science Course 1 (Book 1)

Mo4-L4b: How Do Plants Respond to Chemical Stimuli?

Mo4-L4b How Do Plants Respond to The plant hormone ethylene helps stimulate the
ripening of fruit.
Chemical Stimuli?
KEY CONCEPTS: Ethylene is a gas that can be produced by fruits,
1. How do plants respond to the chemical stimuli, or seeds, flowers, and leaves.
hormones, auxin and ethylene?

Vocabulary A-Z

Let us learn some vocabulary

Key Concept

Plant Hormone How Do Plants Respond to
Chemical Stimuli?
a substance that acts as a chemical messenger How do plants respond to the chemical stimuli,
within a plant. or hormones, auxin and ethylene?
Promotes
Cell Division

Active
Photosynthesis
Suppresses
leaf aging
Increase Yield

Active lateral
Growth
Cytokinin

Let’s Begin

Chemical Stimuli Auxins moves
away from the light
Light
Plant hormones are Concentration Direction
substances that act as increases
chemical messengers
within plants.

Auxins are hormones Stem grows
responsible for faster on Stem grows
phototropism.
dark side towards the
light
They cause the cells on
the dark side of the
plant’s stem to grow
longer. Light causes
destruction
of auxin
Seedling

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