Auxin, a plant growth regulator

Auxin is one of the most important substances in the group of plant hormones, which regulates plant growth and metabolism. This substance is generally stored in the vegetative organs of plants such as apical root meristems (growing root cells), stems and flower buds that are developing, and causes the growth and development of leaves and seed germination. In addition, experiments performed by Darwin, Boysen, and Jensen on oat seedlings showed that auxins at the tips of the branches had a significant effect on stem growth as well as its response to stimuli such as sunlight. In this experiment, oat seedlings were exposed to low light. Phototropism (tendency towards light) showed that the plant stem coleoptile (protective sheath) was inclined towards the light source. However, when the coleoptile tip was cut, the plant did not react to the light stimulus. These studies have conclusively shown that this effect is due to the presence of auxin in the apical meristem. , Impregnated, the rooting process is accelerated. The use of auxins can provide partonocarpy, which is the production of fruit without fertilization, and leads to the formation of seedless fruits.