10 Facts on Gibberellins

In plant biology, gibberellins are one of the main five classes of plant hormones (the others being auxins, cytokinins, abscisic acid (ABA), and ethylene).

Unlike auxins, which encourage root growth, gibberellins are actually used commercially to delay fruit ripening, and otherwise limit plant growth and induces early fruitset as well as seedset. Therefore, its use in indoor growing must be approached carefully.

Here are 10 additional facts on gibberellins:

Gibberellins are Busy

The gibberellins are plant hormones that, among other things, are involved in stem elongation, seed germination, early development, and flower production.

Gibberellins Come in Many Forms

There are 126 known natural and synthetic gibberellins found in not only plants, but also in fungi and bacteria.

Named After a Fungus

Gibberellic acid (GA or GA3), the prototypical gibberellin, is the only hormone named after a fungus.

Gibberellins Go Back Decades

Researchers in pre-World War II Japan discovered that the rice pathogen Gibberella fugikuroi produced a substance causing “foolish seedling disease” in young plants. This substance turned out to be gibberellic acid.

Can Be Applied Directly to Plants

If GA is applied to a plant, it generally results in rapid stem elongation with increased inter-nodal distance.

Lack of Gibberellins Stunt Growth

Dwarfism in a plant is often, but not always, caused by a genetic defect in the pathway for GA production.

Useful in Genetic Studies

The dwarf-tall trait in pea plants that Gregor Mendel studied to unravel the basic laws of genetics results from either a defective or properly functioning gene coding for a protein required for the synthesis of GA.

GA is an Anti-inhibitor

It binds to other molecules inside the cell to prevent them from inhibiting the activation of specific genes. This allows the gene to be “turned on” to produce its product.

Used Commercially

GA is used commercially in some countries to control plant development. For example, to delay fruit ripening.

High Quantities of Gibberellins are Rare

Since the activity of GA is quite powerful, the amount found in plants is relatively low. However, some studies indicate that concentrated GA is a carcinogen.