Yes, plant’s have hormones just like humans do! Hormones are produced naturally by the plant and control plant growth. Let’s discuss the main plant hormones.
Auxin
This is the hormone that is likely in your rooting powder. It is responsible for a lot of responses in a plant. It tells the plant which way is up and down, known as gravitropism, and allows the plant to bend toward the light. This hormone stimulates geotropism, or downward root growth. It also has a hand in flowering, fruit growth and development, vascular development, and apical dominance. Auxin is produced at the tips of plants, so one bud will be the main point of growth while the others are inhibited. Once the main bud is pruned, the dormant lateral buds begin to grow. This is why pruning creates bushy growth!
Cytokinin
This hormone is found in both plants and animals. It as a role in cell division, apical dominance, shoot growth, and fruit development.
Ethylene
You may have heard about putting a banana near unripe fruit to speed up the ripening process. That is because of this hormone, ethylene. This hormone is unique because it is a gas. Besides inducing ripening, it stimulates leaf and flower senescence (the process of plant aging) and abscission (shedding of plant organs like leaves, flowers, fruits and branches)
Gibberellin
This hormone has a role in promoting flowering, cell division, and shoot elongation.
Abscisic Acid
Abscisic acid (ABA) is a plant growth inhibitor. It induces stomatal closure, abscission, and dormancy.
Hormones v. Growth Regulators
Hormones are different from plant growth regulators, which are chemicals created and applied by humans. Plant growth regulators are chemical compounds that mimic natural plant hormones to produce desired changes in plants. These chemicals can be synthetically created or extracted from a natural source. That rooting powder you have is a plant growth regulator! Very small amounts of these substances are needed, were talking parts per million (ppm).
Have a question?
If you have any questions about gardening in Central Florida, please contact UF/IFAS Extension Pasco County at 352-518-0156. For more information on UF/IFAS Extension Pasco County Community Gardens, and how you can join one, visit http://sfyl.ifas.ufl.edu/pasco/. Supervising Agent: Dr. Whitney Elmore.
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More resources
- UF/IFAS Extension Pasco County
- Dr. Whitney Elmore’s Podcast: Rooted in Florida
- Extension Connection: Florida Friendly Landscaping