PLANT PHYSIOLOGY
PLANT GROWTH
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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auxin
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gibberellin
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cytokinin
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ethylene
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Detailed explanation-1: -Unequal distribution of auxin causes phototropism. It causes the plant growth either away or towards the light, based on which part receives light. Auxins are present in higher quantities on the shaded side of a stem. Since auxins promote stem elongation, the shaded part grows taller.
Detailed explanation-2: -Auxins have the opposite effect in roots. This is negative phototropism. In a root the shaded side contains more auxin but grows less. This causes the root to bend away from the light.
Detailed explanation-3: -Light imposes a high degree of control on auxin levels and distribution but its action is not restricted to these processes; light also moderates the sensitivity to auxin within the cell. By imposing control on the nuclear auxin response pathway, light can dampen or amplify the response to auxin.
Detailed explanation-4: -The roots of plants grow away from light.