Gibberellic acid

Gibberellic acid (also called Gibberellin A3, GA, and (GA3) is a hormone found in plants. Its chemical formula is C19H22O6. When purified, it is a white-to-pale-yellow crystalline powder, soluble in ethanol and slightly soluble in water.

Gibberellic acid is a simple gibberellin, promoting growth and elongation of cells. It affects decomposition of plants and helps plants grow if used in small amounts, but eventually plants develop tolerance for it. Gibberellic acid stimulates the cells of germinating seeds to produce mRNA molecules that code for hydrolytic enzymes. Gibberellic acid is a very potent hormone whose natural occurrence in plants controls their development. Since GA regulates growth, applications of very low concentrations can have a profound effect while too much will have the opposite effect. It is usually used in concentrations between 0.01-10 mg/L.

GA was first identified in Japan in 1935, as a metabolic byproduct of the plant pathogen Gibberella fujikuroi (thus the name), which afflicts rice plants; fujikuroi-infected plants develop bakanae ("foolish seedling"), which causes them to grow so much taller than normal that they die from no longer being sturdy enough to support their own weight.

Gibberellins have a number of effects on plant development. They can:

1) stimulate rapid stem growth,

2) induce mitotic division in the leaves of some plants,

3) increase seed germination rate.

Gibberellic acid is sometimes used in laboratory and greenhouse settings to trigger germination in seeds that would otherwise remain dormant. It is also widely used in the grape-growing industry as a hormone to induce the production of larger bundles and bigger grapes, especially Thompson seedless grapes, and in the Okanagan it is used in the cherry industry as a growth regulator.