What is the Difference Between Auxin Gibberellin and Cytokinin

Auxin, gibberellin, and cytokinin are three types of hormones that play major roles in the development of plants. They often interact with each other and with other plant hormones to coordinate growth responses. The main difference between auxin gibberellin and cytokinin is their function.

What is the difference between auxin gibberellin and cytokinin? Auxin mainly performs cell elongation, while gibberellins mainly perform stem elongation, and cytokinin performs cell division.

Key Areas Covered

1. What is Auxin 
      – Definition, Features, Function
2. What is Gibberellin
      – Definition, Features, Function 
3. What is Cytokinin
      – Definition, Features, Structure
4. Similarities Between Auxin Gibberellin and Cytokinin
      – Outline of Common Features
5. Difference Between Auxin Gibberellin and Cytokinin
      – Comparison of Key Differences
6. FAQ: Auxin Gibberellin and Cytokinin
      – Answers to Frequently Asked Questions

Key Terms

Auxin, Gibberellin, Cytokinin, Plant Hormone

What is Auxin

Auxins are a group of plant hormones produced in shoot tips, young leaves, and root tips. These hormones are involved in a wide range of physiological processes. Auxins are involved in phototropism, the directional growth of plants in response to light. When light falls on one side of the plant, auxins accumulate on the other side (shaded side). This accumulation causes the cells to elongate. This differential growth results in the stem bending towards the light. A similar process also occurs in gravitropism, where roots grow downward in response to gravity.

Figure 1: Indole-3-Acetic Acid

Auxins also promote cell elongation, leading to stem and root growth.  Auxins are involved in apical dominance, root initiation, fruit development, and abscission. Moreover, synthetic auxins are used in various applications in agriculture to control weeds, as rooting hormones, and to induce fruit formation without pollination.

What is Gibberellin

Gibberellins are a group of plant hormones produced in young leaves, roots, and seeds. They are transported throughout the plant to bring about their effects.

Figure 2: Gibberellin A1

Gibberellins promote stem elongation. By stimulating cell division and elongation, these hormones contribute to increased plant height. Gibberellins also involved in seed germination. This is achieved by stimulating the production of enzymes that break down stored food reserves in the seed. Gibberellins also influence fruit and flower development.

What is Cytokinin

Cytokinins are a group of plant hormones mainly produced in root tips, young leaves, and developing fruits. One main function of cytokinin is cell division.  They stimulate cell proliferation. This is particularly important in shoot and root development, as well as in the formation of organs like leaves and flowers.

Figure 3: Zeatin

Cytokinins are involved in plant aging by delaying the aging process, in apical dominance, and in organ differentiation. They also influence the development of chloroplasts.

Similarities Between Auxin Gibberellin and Cytokinin

1. All three hormones are essential for plant growth and development.
2. Each hormone uses specific transport mechanisms within the plant.
3. Moreover, they often interact with each other and with other plant hormones to coordinate growth responses.

Difference Between Auxin Gibberellin and Cytokinin

Definition

• Auxins are a type of plant hormones that promote the elongation of shoot cells in plants while cytokinins are a type of plant hormones that promote cell division in plant roots and shoots. Meanwhile, gibberellins are a type of plant hormones that regulate developmental processes, like stem elongation, flowering, germination, dormancy, and leaf and fruit senescence.

Function

• Auxins are mainly involved in cell elongation and apical dominance, while gibberellins are mainly involved in stem elongation, seed germination, and breaking dormancy. Cytokinins mainly help in cell division and differentiation.

Location

• Auxins are mainly produced in the shoot apex, young leaves, and buds, and gibberellins are mainly produced in young leaves, roots, and seed embryos, while cytokinins are mainly produced in root tips, young leaves, and developing fruits.

Transportation

• Auxins are typically transported basipetally (from shoot to root), while gibberellins are transported both acropetally (from root to shoot) and basipetally. Cytokinins, on the other hand, are transported acropetally (from root to shoot).

Conclusion

In brief, the main difference between auxin gibberellin and cytokinin is their function. Auxin mainly perform cell elongation, while gibberellins mainly perform stem elongation, and cytokinin perform cell division. In addition, they are produced by different parts of the body and transported throughout the plants using different mechanisms.

FAQ: Auxin Gibberellin and Cytokinin

1. How do auxins, gibberellins, and cytokinins promote growth?

Auxins, gibberellins, and cytokinins are plant hormones that stimulate growth. Auxins promote cell elongation and root development. Gibberellins trigger stem elongation and seed germination. Cytokinins induce cell division and counteract aging.

2. What is the function of cytokinin?

Cytokinins are plant hormones that primarily stimulate cell division. They also influence shoot development, leaf expansion, and delay leaf aging. Cytokinins interact with other hormones to regulate overall plant growth.

3. What are the effects of gibberellins?

Gibberellins are plant hormones that promote growth, seed germination, stem elongation, and flowering. They also influence fruit development and breaking seed dormancy.

4. What is the role of cytokinins in flowering?

Cytokinins promote cell division in the shoot apical meristem. They also influence the development of floral organs like petals and sepals, playing a vital role in the overall flowering process.

5. Where is gibberellin produced?

Gibberellins are mainly produced in young leaves, root tips, and seed embryos. They are also synthesized in certain fungi.

Reference:

1. “Auxin – An Overview.” Science Direct.
2. “Gibberellin.” Wikipedia. Wikipedia Foundation.
3. “Cytokinin.” Wikipedia. Wikipedia Foundation.

Image Courtesy:

1. “Indol-3-ylacetic acid” By  Ayacop assumed – Own work assumed (based on copyright claims). (Public Domain) via Commons Wikimedia
2. “Gibberellin A1 v2” By User:Innerstream – Own work (Public Domain) via Commons Wikimedia
3. “Zeatin” By Edgar181 – Own work (Public Domain) via Commons Wikimedia