Just as animals' bodies contain various hormones to control and regulate metabolism and other life processes, plants also produce their own hormones. Auxins and gibberellins are plant hormones that play key roles in basic growth in green plants. Although independent chemicals, they act in various degrees of unison or opposition to create strong, balanced stems and leaves on an individual plant.
Gibberellic acid (GA) is a potent growth hormone that is known as a gibberellin. GA is manufactured within the plant or is already present within a seed. According to the Plant Hormones website, gibberellins are grouped according to their growth effects as well as their molecular structure. There are currently 136 different gibberellins known to exist in both flowering and nonflowering plants, bacteria and fungi.
All gibberellins promote plant tissue growth via cell division and elongation. John A. Riley writes on the California Rare Fruits Growers website that GA holds key functions in plants. Gibberellins are central in seed germination and can promote increased lateral stem growth and early flowering.
Sprouting and growth of seeds and young seedling plants is an inherent and necessary benefit of GA. Presence of GA in plants leads to flower production, increased setting of fruits (if pollination is facilitated) as well as increased growth of fruits, Riley says. Increased tissue growth leads to more leaf and stem growth and can also render a temporary toughness to flower buds when untimely frosts occur in early spring.
Gardeners and commercial farmers employ the application of GA to increase crop plants' branching, flowering and production of fruits. Treating seeds with high levels of GA can break the dormancy, decreasing the length of time a seed must "rest" before sprouting. Treatment of plants can also lead to controlled timing or production of flowers and fruits to the gardener's or farmer's schedule. Moreover, spraying plants with the hormone can create larger plants in a shorter time for sale at a nursery or during a shorter growing season. Spraying fruit trees that are blooming can protect them when a frost is predicted to potentially kill exposed flower petals.
While plants naturally create GA and other gibberrelins, humans can manufacturer GA and apply it to plants to manipulate growth. The California Rare Fruit Growers site mentions that you cannot blindly apply GA on plants for benefits. According to plant species as well as natural timing of the plant's growth, GA must be applied at appropriate times to yield desired effects, such as flowering. It is possible to over-apply GA to a "potent" level to cause a plant to grow so quickly that it becomes structurally weak and collapses.