- S-adenosyl methionine is a precursor of which plant hormone?
(1) Absiccic acid (2) Auxin
(3) Ethylene (4) Cytokinin
Correct answer: (3) Ethylene
Explanation:
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S-adenosyl methionine (SAM) is a crucial precursor in the biosynthesis of ethylene, a key plant hormone that regulates various physiological processes including fruit ripening, senescence, and stress responses.
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In the ethylene biosynthesis pathway, SAM is converted to 1-aminocyclopropane-1-carboxylic acid (ACC) by ACC synthase, and ACC is further converted to ethylene by ACC oxidase.
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SAM is not a precursor for abscisic acid, auxin, or cytokinins; these hormones have distinct biosynthetic origins.
Option details:
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(1) Abscisic acid — synthesized from carotenoid precursors, not SAM.
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(2) Auxin — mainly synthesized from tryptophan.
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(3) Ethylene — correct; synthesized via SAM as an intermediate.
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(4) Cytokinin — synthesized from adenine derivatives, not SAM.
S-adenosyl methionine plays a vital role in ethylene production in plants, linking methionine metabolism to hormone regulation essential for plant development and adaptation.
4 Comments
Sonal Nagar
November 29, 2025Ethylene
Manisha choudhary
November 29, 2025Ethylene biosynthesis m SAM key precursor h
Methionine s bnta h sam synthase enzyme or methionine adenosyl transferase enzyme k through sam s formic acid CO2 NH2 REALSE hota h O2 add hota h ethylene bnta h
Manisha choudhary
November 29, 2025Sorry sorry sir sam s acc bnta h acc s realse hota h formic acid ,CO2 NH2 ,O2 add hota h ACC s ethylene bnta h
Sakshi Kanwar
December 1, 2025Ethylene