Difference Between Auxin and Cytokinin

The key difference between auxin and cytokinin is that the auxin stimulates root branching while the cytokinin inhibits root branching and the lateral root formation. To add more to this, auxin is mainly responsible for elongation of cells in the stem and root tips whereas, cytokinins are mainly responsible for cell division and hence, they are found in growing areas.

Phytohormones also known as plant hormones are important chemical substances for plant growth and development. They are organic molecules, and they work as signalling molecules that regulate the plant development. There are five major types of plant hormones: auxin, gibberellin, cytokinin, ethylene, and abscisic acid. Thus, they perform different functions alone and together to influence plant growth.

CONTENTS

1. Overview and Key Difference
2. What is Auxin
3. What is Cytokinin
4. Similarities Between Auxin and Cytokinin
5. Side by Side Comparison – Auxin vs Cytokinin in Tabular Form
6. Summary

What is Auxin?

Auxin is a powerful plant hormone. It produces in low concentrations naturally by plants in the roots, buds and shoots tips. Auxin is mainly responsible for stem elongation. Furthermore, it prevents the growth of lateral buds and maintains apical dominance. Gardener trims or cuts the tips of the shoots. Then the plants become bushier since auxin is not produced and the effect of apical dominance is no longer maintained.

Moreover, Auxin is important in phototropism as well because auxin moves to the darker side of the plant and causes for cell division. In turn, it causes for the curvature of the plants stem towards the light. Other than these functions, auxin is responsible for stimulating root development, promoting fruit development, secondary growth of the plants,

What is Cytokinin?

Cytokinin is one of the five types of plant hormones. It promotes cell division and cell differentiation. They occur in almost every tissue of the plant. But they are abundant in growing tissues such as root tip, shoot apex, cambium, and immature organs, etc. They are adenine derivatives.

Plant roots synthesize cytokinins and then produced cytokinins move upwards via the xylem. Cytokinins promote lateral bud formation. Furthermore, it promotes lateral root formation, leaf senescence, morphogenesis, nodule formation, etc. as well.

What are the Similarities Between Auxin and Cytokinin?

• Auxin and Cytokinin are plant hormones.
• They are produced in low concentrations.
• Both are organic molecules.
• Auxin and Cytokinin are responsible for cell division, elongation, etc.

What is the Difference Between Auxin and Cytokinin?

Out of the five categories of plant hormones, auxin and cytokinin are two key types that affect cell division, cellular expansion, cell differentiation, etc. Auxin is mainly responsible for stem elongation while cytokinin is responsible for cell division and differentiation. The below infographic presents more details on the difference between auxin and cytokinin in a tabular form.

Summary – Auxin vs Cytokinin

Auxin and cytokinin are key plant hormones essential for plant development. Both types regulate almost all aspects of plant growth and development. Indole acetic acid is the most abundant form of auxin while cytokinins are adenine derivatives. Auxin is mainly responsible for elongation of cells in the stem and root tips. Cytokinins are mainly responsible for cell division and hence, they are found in growing areas. This is the difference between auxin and cytokinin.

Reference:

1.“Cytokinins.” Egyptian Journal of Medical Human Genetics, Elsevier. Available here  
2.“Auxin.” Wikipedia, Wikimedia Foundation, 3 Aug. 2018. Available here 

Image Courtesy:

1.”Model for auxin transport”By Andyh12 – Own work, (CC BY-SA 3.0) via Commons Wikimedia
2.”Zeatin”By Edgar181 – Own work, (Public Domain)  via Commons Wikimedia