The Effect of Gibberellic Acid


Scientists are working daily to understand plants better---the hope is that scientists can figure out what properties the chemicals in plants have so that they might be used to improve horticulture and human health. In investigating the many species of plants that have been discovered thus far, scientists have discovered the effects of one of the many chemicals plants contain. That chemical is gibberellic acid.


Gibberellic acid is a chemical found in plants that is related to plant growth. Specifically, the growth hormone causes plant cells to grow and to elongate. The 79 types of gibberellic acid are found in varying combinations depending on which plant is studied. One plant may have up to a dozen or more forms of gibberellic acid, with each form controlling the plant in a specific way.


Like other plant hormones, gibberellic acid can impact the dormancy of a plant. It has been found to promote germination of seeds, thus it is used as a natural means of starting seedlings. This is important to horticulture and agriculture because increased germination usually results in higher yields.


Although the main function of gibberellic acid is to make a plant grow bigger, gibberellic acid also can have the opposite effect if found in quantities that are too large or too small. The amount has to be just right or the plant won't grow or will die. Plants that are considered short for the species often are found to have insufficient levels of gibberellic acid.

Fruit Yield

Gibberellic acid is connected to the timing of fruit generation. In onions, for example, gibberellic acid corresponds to the suppression of bulb formation. When the levels of acid are correct and interact with the plant's genetic makeup appropriately, the plant stops suppressing bulb formation and the onion bulb grows. Gibberellic acid is sprayed on most seedless grapes to create larger grapes in larger bunches, and for this reason it is important to the wine industry.

Plant Sex

Gibberellic acid is connected to sex differentiation in plants as well as growth. Plants such as spinach, corn and hemp become male or female depending on the levels and combinations of gibberellic acid present. This is important because both male and female forms of a plant usually are needed to have good plant pollination and reproduction---if farmers or gardeners notice an unusually large yield of one sex or the other, they may solve the problem through applications of gibberellic acid.

About this Author

Wanda Thibodeaux is a freelance writer and editor based in Eagan, Minn. She has been published in both print and Web publications and has written on everything from fly fishing to parenting. She currently works through her business Web site,, which functions globally and welcomes new clients.