- Which of the following plant hormones can mimic the det1 mutation, causing de-etiolation and chloroplast development in dark?
(1) Cytokinin (2) Gibberellin
(3) Auxin (4) Ethylene
Correct answer: (1) Cytokinin
Explanation:
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The det1 mutation in Arabidopsis causes de-etiolation (light-grown characteristics) even in darkness, including chloroplast development and inhibition of hypocotyl elongation.
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Among plant hormones, cytokinin can mimic the det1 mutation effects by promoting chloroplast development and other photomorphogenic responses even in the absence of light.
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(2) Gibberellin promotes elongation growth typically associated with etiolation, so it does not mimic det1.
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(3) Auxin primarily promotes elongation growth and does not induce de-etiolation.
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(4) Ethylene influences many developmental processes but is not known to mimic det1 de-etiolation effects.
Option-wise:
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Cytokinin — correct; mimics det1 de-etiolation in dark.
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Gibberellin — promotes etiolation growth, contrary to det1 effects.
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Auxin — elongation promoter, no det1 mimicry.
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Ethylene — unrelated.
Cytokinin mimics the det1 mutation by inducing light-dependent development such as de-etiolation and chloroplast formation even in the dark, highlighting its crucial role in photomorphogenic signaling pathways in plants.
