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Plant growth regulator: a chemical produced by plant cells that regulates growth and differentiation
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Plants can modify their growth and differentiation through plant growth regulator
Tropism: a directional change in growth/ movement in response to a stimulus
Phototropism: a change in direction of a growing plant in response to light
Gravitropism: a directional change in growth pattern in response to gravity
Thigmotropism: a directional change in growth pattern in response to touch
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