Gibberellin biosynthesis and inhibitors

Dwarfing agents (gibberellin biosynthesis inhibitors) are frequently used to manipulate plant size. This is done through interference with the biosynthetic process. There are three major groups of inhibitors of GA-biosynthesis (see fig.1):
  • onium-type compounds
    • chlormequat chloride (CCC)
  • compounds with N-containing heterocycle
    • pirimidines: ancymidol, flurprimidol
    • norbornanodiazetins: tetcyclacis
    • triazoles: paclobutrazol (Bonzi), uniconazole
    • imidazoles
  • cyclohexane-triones
    • cimectacarb
    • prohexadione calcium

Points of inhibition of GA biosynthesis by plant growth
retardants (Rademacher, 1991) legend: MVA: mevalonic
acid; IPP: isopentenyl pyrophosphate; GPP: geranyl
pyrophosphate;FPP: farnesyl pyrophosphate; GGPP:
geranylgeranyl pyrophosphate; CPP: coplyl pyrophosphate