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Question
Name a plant hormone responsible for bending of a shoot of a plant when it is exposed to unidirectional light. How does is promote phototropism?
Solution
Auxin is the plant hormone that causes a plant's shoot to bend when it is exposed to unidirectional light. Auxin accumulates on the side of the shoot that is shaded, causing the cells on that side to elongate more than the cells on the side that is exposed to light, which causes the shoot to bend in the direction of the light source.
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