Exploring plant growth regulators (PGRS): Classification, structural features, and functional significance

The discovery of plant growth regulators, or phytohormones, has revolutionized horticulture by offering means to control virtually all aspects of plant growth and development, thereby enhancing production, quality, and the post-harvest life of crops. This impact is particularly evident in the production of tree fruits, where even minor enhancements can significantly improve productivity, product quality, and consumer appeal, thus increasing the value of these high-value crops. Phytohormonesdespite being produced in minute quantities by plants, exhibit potent physiological activity. Among these, auxins and cytokinin are primary categories, with auxins produced in apical meristems, young leaves, seeds, and fruits to promote shoot elongation and root initiation, and cytokinin generated in root tips, seeds, and unripe fruits to encourage lateral shoot growth and cell division. The study delves into the role of the plant hormone auxin as a key signaling molecule throughout all stages of plant growth, highlighting its involvement in a myriad of developmental processes. Recent research has shed light on the molecular details of auxin responses, elucidating the roles and control mechanisms of the canonical transcriptional auxin response and categorizing the molecular processes underlying various auxin-mediated effects on plant development.