The Effect of Gibberellic Acid on Seed Germination

Seed Dormancy

• Presoaking seeds in gibberellic acid solution causes the rapid germination of highly dormant seeds that otherwise would need cold treatment, after-ripening or aging, or other prolonged pretreatments. Some gardeners are able to make old seeds more viable, that is, more likely to germinate. Soaking old seeds in gibberellic acid solution encourages synthesis of the hormones that make germination possible.

Stem Growth

• Gibberellic acid also controls shoot elongation in many plants. In small quantities, gibberellic acid can boost the growth of plants. However, if applied in too large a quantity, it can cause the plant to grow too quickly and collapse under its own weight. This effect can be seen in the effects of the Gibberella fujikuroi fungus on rice plants. The dwarf forms of some plants are due to GA deficiencies. As a result, treatment of these plant varieties with gibberellic acid can result in the loss of the dwarf traits in the specimen.

Solution Concentrations

• In his study on the effect of gibberellic acid on fruit set and seed germination, John Riley suggests a solution of 2000 ppm of gibberellic acid for seed germination. This is equivalent to 125 mg of gibberellic acid dissolved in 1/4 cup of water. However, both studies published in "Plant Physiology" showed results with lower concentrations.

Caution

• Though it is not listed as a poison, you should be careful while mixing or applying gibberellic acid to your plants. Avoid ingesting the chemical. If some of the solution comes into contact with your eyes, flush the area immediately with clean water. If spilled on your skin, wash with soap and water.