Correct option is C
Explanation:
· Auxins are primarily synthesized from Tryptophan, an amino acid precursor in plants.
· Cytokinins, like Zeatin, are synthesized from adenine-type compounds.
· Ethylene is produced from S-adenosyl methionine (SAM) via ACC, a key precursor.
· Gibberellins are terpenoid compounds derived from Geranylgeranyl diphosphate (GGPP).
Additional Knowledge:
(A) Auxins (Tryptophan Precursor):
-Auxins regulate apical dominance, phototropism, and root formation.
-Synthetic auxins like 2,4-D are used as herbicides.
(B) Cytokinins (Adenosine Moiety Precursor):
-These hormones promote shoot growth, delay leaf aging, and enhance nutrient mobilization.
-The ratio of auxins to cytokinins determines organ differentiation in tissue culture.
(C) Ethylene (ACC Precursor):
-Ethylene regulates fruit ripening (e.g., bananas, tomatoes) and response to mechanical stress.
-Commercially, ethylene inhibitors like 1-MCP are used to delay ripening.
(D) Gibberellins (GGPP Precursor):
-They stimulate seed germination, break dormancy, and enhance stem elongation.
-Farmers use GA sprays in grapes and sugarcane for yield improvement.
