What are plant hormones and why are they important? Here we will introduce a few common hormones and their functions, including cytokinins for root development.
What They Are
Plant hormones, also called phytohormones or plant growth factors, are signal molecules essential to plant growth. Unlike animals, which have glands to secrete hormones in the body, plants produce hormones in every cell, in low concentrations. These hormones have different functions in the physiology of the plant, from determining the formation of stems, leaves, and flowers to regulating fruit and even the death of the plant.
While plants produce their own hormones naturally, similar hormones produced by microorganisms and fungi can be added to the plant through shared soil. Hormones are produced and used for local cell functions, but the plant is also able to move those chemicals to different areas through processes of cytoplasmic streaming within the cell, slow diffusion between cells, and vascular tissues between different areas of the plant.
Types of Plant Hormones
The very low concentrations of hormones within a plant make them difficult to study. However, there are five major classes of formally recognized plant hormones. These groups contain hormones with similar chemical structures, all of which carry out both positive and inhibitory functions within the plant.
Auxins are responsible for cell elongation and enlargement in the stems of plants. They stimulate bud formation, root initiation, and seed protein synthesis. In tandem with cytokinins, they promote cell division in various tissues. In large quantity, auxins are toxic to plants, which is why they are often used in man-made synthetic herbicides.
Gibberellic Acid (GAs) are a large group of chemicals that are responsible for stem elongation, seed germination, and production of enzymes that aid in food production. GAs also affects seed dormancy and causes plants to bolt or flower as a result of long days.
Ethylene is a single gaseous compound that is produced in the breakdown of methionine, which is present in all cells. It is in greatest quantity in early stages of germination and growth, after which point it diffuses out of the cell and out of the plant. Ethylene is responsible for fruit ripening and cell shape and growth. It strengthens stems and even larger branches and trunks when they encounter obstacles.
- Abscisic Acid
Abscisic Acid (ABA) is a single compound primarily produced in chloroplasts in the leaves of a plant, and it plays many essential inhibiting roles. It inhibits shoot growth and is responsible for bud and seed dormancy, which protects against premature winter growth. ABA also closes the plant’s stomata when it is under water stress.
Cytokinins are a group of chemicals responsible for promoting cell division in the plant. They also stimulate shoot initiation and bud formation, leaf expansion, and tissue longevity. They work closely with auxins and regulate their transport through the plant. Cytokinins can be added to the plant by other organisms, such as by secretion of plant active hormones which are taken through the root structure. This is what our Microp product achieves using cyanobacteria.
Boosting Plant Hormones
Because small microorganisms can also produce some of these same plant hormones, it is possible to aid the plant with these additional essential biochemicals. Here at Soil Technologies Corp., we believe in harnessing the power of natural plant hormone production to boost crop growth.
Our Microp products use cyanobacteria as a biofertilizer, which also produces cytokinin hormones. Once applied to the soil where a crop is growing, the cyanobacteria will release cytokinins into the soil chemistry. The cytokinins are then available to the plant and translocated to the growing point of the root, where they stimulate cell division and thereby expand the root structure.