Final answer:
Auxin is the hormone responsible for various plant growth processes, including apical dominance, vascular tissue differentiation, and fruit formation, as well as influencing the arrangement of leaves and promoting lateral root formation.
Step-by-step explanation:
The hormone that is involved in apical dominance, vascular tissue differentiation, arrangement of leaves, formation of the vascular cambium, fruit formation, and lateral root formation is called auxin. Auxin, particularly indole-3-acetic acid (IAA), is a naturally occurring plant hormone that plays a crucial role in regulating various aspects of plant growth and development. This hormone is primarily responsible for cell elongation and is active in processes such as phototropism and gravitropism. It is produced in the apical meristem and controls the phenomenon of apical dominance by inhibiting the growth of lateral buds when present in high concentrations. Moreover, auxins also influence the differentiation of meristem into vascular tissue and are involved in leaf development and arrangement. The commercial application of auxins includes promoting rooting in cuttings, synchronizing fruit setting, and enhancing fruit development.