Phytohormones , are naturally occurring small organic molecules or substances which influence physiological processes in plants at very low concentrations (Davies, 2004). In other words, phytohormones are chemical messengers that coordinate cellular activities of plants

Phytohormones are Regulators synthesised by plants and influencing physiological processes

Phytohormones are organic compounds synthesised by plants that regulate various physiological processes. They are also known as plant hormones and play a vital role in the growth and development of plants. These hormones are produced in small quantities and are transported to different parts of the plant where they regulate various processes such as growth, development, and response to environmental cues.

Types of Phytohormones

There are five main types of phytohormones:

1. Auxins - These hormones are responsible for cell elongation and differentiation, apical dominance, and tropisms.

2. Gibberellins - These hormones promote stem elongation, seed germination, and fruit and flower development.

3. Cytokinins - These hormones promote cell division, delay senescence, and regulate the development of shoot and root meristems.

4. Abscisic Acid - This hormone regulates seed dormancy, stomatal closure, and drought tolerance.

5. Ethylene - This hormone regulates fruit ripening, abscission, and senescence.

Functions of Phytohormones

Phytohormones have various functions such as:

1. Regulating plant growth and development

2. Stimulating or inhibiting cell division and differentiation

3. Regulating apical dominance

4. Regulating tropisms

5. Regulating seed germination and fruit development

6. Regulating response to environmental cues such as light, temperature, and water availability

7. Regulating stress responses such as drought, salinity, and pathogen attack

Conclusion

Phytohormones play a crucial role in regulating the growth and development of plants. They are synthesised in small quantities and transported to different parts of the plant where they regulate various physiological processes. There are five main types of phytohormones, each with specific functions. Understanding the role of phytohormones is essential for developing strategies to improve crop yields and enhance plant growth and development.