Gibberellic acid refers to a group of compounds called gibberellins. The first compound was discovered by Japanese plant pathologists who were investigating the cause of a disease that caused rice seedlings to elongate and die.
Discoveries in Japan
In the late 1800s a disease called bakanae---"foolish seedling"---attacked rice plants in Japan, Taiwan and other Asian countries. The plants exhibited extended growth patterns and then died. A Japanese plant pathologist, Shotaro Hori, proved the cause of the disease was a fungus, which was later named Gibberella fujikuroi. In 1926, Eiichi Kurdsawa identified a chemical in the fungus that caused the disease. In 1935, Teijiro Yabuta isolated a non-crystalline substance called a gibberellin that affected the growth of rice. Three years later, Yabuta and Yasuki Sumiki isolated another gibberellin from the fungus.
Discoveries in the United States
Scientists in the United States did not begin researching gibberellins until after World War II. In 1950, John E. Mitchell of the Research Unit at Camp Dietrick, Maryland, began researching the fungus and gibberellins. He worked in coordination with the northern regional research labs of the United States Department of Agriculture in Peoria, Illinois, to develop a fermentation process to extract pure gibberellic acid for agricultural use.
Scientists in the United Kingdom were also working with gibberellins in the 1950s. Experiments conducted by Akers Research Lab produced the same results as experiments in the United States. The compound was named gibberellic acid. In 1955, members of the Japanese group headed by Sumiki produced gibberellic acid, in addition to three other gibberellins. Since then between 100 and 150 gibberellins have been discovered in rice, wheat, barley, maize, corn and other plants.
Uses of Gibberellic Acid
Gibberellic acid is used to stimulate germination of seedlings that may usually need scarifying, a cold period or some other treatment. It is also used to help pollination of closely related species or self-pollinated clones of plants. Gibberellic acid can induce early flowering and improve fruiting of plants.
How Gibberellic Acid Is Produced
Producers grow the fungus, Gibberella fujikuroi, in huge vats. Then the gibberellic acid is extracted from the fungus and purified. The gibberellic acid is sold as a powder or a liquid. It has been available commercially since the late 1950s.