Physiological Effects of Plant Growth Regulators

Having seen how the five major groups of plant growth regulators were discovered, we can now look at some of the physiological effects that each of these categories produces in plants. Although the five PGRs — auxins, gibberellins, cytokinins, ethylene and abscisic acid — are distinct molecules, their effects overlap a great deal.

• A single PGR can influence many different processes in the plant.
• The same process can often be affected by more than one PGR.
• Two PGRs may work in the same direction (synergistically) or in opposite directions (antagonistically) on a given event. …