Precursor of PGRs Auxin - Tryptophan ( Zn) Gibberelin - Ent - Kaurene (Acetyle Co-enzyme ) Cytokinin - Adenine ( Adenosine Monophosphate ) AMP Ethylene - Methionine (Aminocyclopropane -1- carboxylic acid) ACC ABA - Violaxanthin 569 views10:25