what are phytohormones

Phytohormones, also known as plant hormones, are chemical compounds produced naturally by plants that act as chemical messengers to regulate various physiological processes. They occur in very low concentrations and control plant growth, development, stress responses, and defense against pathogens. Phytohormones coordinate processes such as cell division and elongation, tissue differentiation, flowering, seed germination, fruit ripening, and adaptation to environmental stress. The main types of phytohormones include auxins, gibberellins, cytokinins, abscisic acid, ethylene, brassinosteroids, jasmonates, and strigolactones. Each type has specific roles, such as auxins promoting cell elongation and apical dominance, gibberellins aiding seed germination and flowering, cytokinins promoting cell division, and abscisic acid regulating stomatal closure and seed dormancy. Phytohormones can also interact synergistically or antagonistically to fine-tune plant responses. These hormones are produced in various parts of the plant like roots, stems, leaves, and fruits, and they move through the plant to target sites through vascular tissues. Phytohormones are fundamental for plant adaptation and survival under changing environmental conditions and are also widely used in agriculture to regulate crop growth and improve yields with both natural and synthetic forms.