Gibberellic acid (also called Gibberellin A3, GA, and GA3) is a hormone found in plants and fungi . Its chemical formula is C19H22O6. When purified, it is a white to pale-yellow solid.
Plants in their normal state produce low amounts of GA3. It is possible to produce the hormone industrially using microorganisms. Nowadays, it is produced by submerse fermentation, but this process presented low yield with high production costs and hence higher sale value. One alternative process to reduce costs of the GA3 production is Solid-State Fermentation (SSF) that allows the use of agro-industrial residues. Gibberellic acid is a simple gibberellin, a pentacyclic diterpene acid 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 to it. GA 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 and 10 mg/L.
GA can stimulate rapid stem and root growth, induce mitotic division in the leaves of some plants, and increase seed germination rate.
When seeds absorb water, the hormone gibberillin appears in the embryo and is translocated to the aleurone layer, where it activates the metabolism to initiate sprouting. Gibberillin causes the rapid growth of beans and bamboo, which contain large amounts of the hormone.
Gibberillin is not, however, appropriate for application to all plants. In most cases, gibberillin increases the thickness and internodal length of the stalk. Sometimes the terminal nodes are weak branching is suppressed, and the roots develop poorly. The number of flowers increase, and they are larger. Germination and flowering are stimulated, but leaf growth and chlorophyll production are reduced proportionately.
Gibberillin is extracted from cucumber seeds, fresh cantelope seeds, dried corn kernels, and from pencil rod, lupine, and pinto beans. Soak 200 gr of powdered seeds for one week in 110 ml of a mixture of acetone (10 parts), isopropyl alcohol (5 parts) ethanol (2 parts) and water (5 parts). Filter the mush and rinse it with 20 ml acetone and 20 ml isopropyl alcohol. Combine the rinse and mother liquor, evaporate the solvent, and dissolve the residual gum in alkaline water for experimental use.