A '''tropism''' is a movement or growth in a plant that is a response to a stimulus. It differs from a [[taxis]], which implies [[motility]], or independent movement. Common tropisms include phototropism, which is a response to light, and heliotropism, in which portions of plants such as leaves and flowers turn toward the [[sun]].
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A '''tropism''' is a movement or growth in a plant that is a response to a stimulus. It differs from a [[taxis]], which implies [[motility]], or independent movement. Common tropisms include phototropism, which is a response to light, and heliotropism, in which portions of plants such as leaves and flowers turn toward the [[sun]]. Gravitropism refers to the effect that the direction of [[gravity]] has on which direction a plant grows.