Gibberellic acid (also called gibberellin A3, GA, and GA₃) is a

hormone A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are require ...

found in plants and fungi. Its

chemical formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbol ...

is C₁₉H₂₂O₆. When purified, it is a white to pale-yellow solid. Plants in their normal state produce large amounts of GA3. It is possible to produce the hormone industrially using microorganisms.Camara, M. C. et al (2015) General Aspects and Applications of Gibberelins and Gibberellic Acid in Plants. In: Hardy, J.. (Org.). Gibberellins and Gibberellic Acid: Biosynthesis, Regulation and Physiological Effects. 1ed.Hauppauge: Nova Science Publishers, 2015, v., p. 1-21. Gibberellic acid is a simple

gibberellin Gibberellins (GAs) are plant hormones that regulate various developmental processes, including stem elongation, germination, dormancy, flowering, flower development, and leaf and fruit senescence. GAs are one of the longest-known classes of plan ...

, a

pentacyclic A cyclic flower is a flower type formed out of a series of whorls; sets of identical organs attached around the axis at the same point. Most flowers consist of a single whorl of sepals termed a calyx; a single whorl of petals termed a corolla; on ...

diterpene Diterpenes are a class of chemical compounds composed of four isoprene units, often with the molecular formula C20H32. They are biosynthesized by plants, animals and fungi via the HMG-CoA reductase pathway, with geranylgeranyl pyrophosphate being ...

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 In molecular biology, messenger ribonucleic acid (mRNA) is a single-stranded molecule of RNA that corresponds to the genetic sequence of a gene, and is read by a ribosome in the process of synthesizing a protein. mRNA is created during the ...

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 was first identified in Japan in 1926, as a metabolic by-product of the plant pathogen ''

Gibberella fujikuroi ''Gibberella fujikuroi'' is a fungal plant pathogen. It causes ''bakanae'' disease in rice seedlings. Another name is foolish seedling disease. It gets that name because the seeds can be infected, leading to disparate outcomes for the plant. Th ...

'' (thus the name), which afflicts

rice Rice is the seed of the grass species '' Oryza sativa'' (Asian rice) or less commonly ''Oryza glaberrima'' (African rice). The name wild rice is usually used for species of the genera '' Zizania'' and '' Porteresia'', both wild and domesticat ...

plants. ''Fujikuroi''-infected plants develop ''

bakanae or bakanae disease (, , ), from the Japanese for "foolish seedling", is a disease that infects the rice plant. It is caused by the fungus '' Gibberella fujikuroi'', the metabolism of which produces a surplus of gibberellic acid. In the plant, this ...

'' ("foolish seedling"), which causes them to rapidly elongate beyond their normal adult height. The plants subsequently

lodge Lodge is originally a term for a relatively small building, often associated with a larger one. Lodge or The Lodge may refer to: Buildings and structures Specific * The Lodge (Australia), the official Canberra residence of the Prime Ministe ...

due to lack of support, and die. Gibberellins have a number of effects on plant development. They can stimulate rapid stem and root growth, induce

mitotic division In cell biology, mitosis () is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis gives rise to genetically identical cells in which the total number of chromosomes is mainta ...

in the leaves of some plants, and increase seed germination rates. 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 bunches and bigger grapes, especially

Thompson seedless The sultana is a "white" (pale green), oval seedless grape variety also called the sultanina, Thompson Seedless (United States), Lady de Coverly (England), and oval-fruited Kishmish (Iraq, Iran, Israel, Palestine, Pakistan, Afghanistan, India) ...

grapes. In the

Okanagan The Okanagan ( ), also known as the Okanagan Valley and sometimes as the Okanagan Country, is a region in the Canadian province of British Columbia defined by the basin of Okanagan Lake and the Canadian portion of the Okanagan River. It is par ...

and Creston valleys, it is also used as a growth regulator in the cherry industry. It is used on Clementine Mandarin oranges, which may otherwise cross-pollinate with other citrus and produce undesirable seeds. Applied directly on the blossoms as a spray, it allows for Clementines to produce a full crop of seedless fruit. GA is widely used in the barley malting industry. A GA solution is sprayed on the barley after the steeping process is completed. This stimulates growth in otherwise partly dormant kernels and produces a uniform and rapid growth.

References

{{Authority control Plant hormones Cyclohexenols Tertiary alcohols Lactones Heterocyclic compounds with 5 rings Vinylidene compounds

See also

References