october 13, 2014 pick up your table’s journals. write “forces in plants” in the table of...
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October 13, 2014
Pick up your table’s journals.Write “Forces in Plants” in the table
of contents.Forces in Plants page 20
Introduction
When someone touches you, you turn and look.When you hear a loud noise, you may jump.
These are known as STIMULUS and RESPONSE.Something happens and causes another thing to
respond.
TROPISMS
• In plants, a response to a stimulus is called a TROPISM.
Forces cause the plant to respond.There are several different tropisms that you will need to know:
Back up to page 18
• Geotropism (Gravitropism) – a plant’s response to the force of gravity
Roots grow down – stems grow up(positive) (negative)
Phototropism – A plant’s response to light – grows toward the
light
Thigmotropism – a plant’s response to touch
Turgor pressure – force of water pushing against cell walls in plants
Gravitropism (geotropism)
Phototropism
Thigmotropism
Hydrotropism
Turgor Pressure
• Force of water pushing against cell walls in plants.
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