1-Aminocyclopropanecarboxylic acid hydrochloride (ACC·HCl) is primarily used in biochemical and plant physiology research to investigate the role of ethylene, a key plant hormone, in growth and development processes. As the immediate precursor in the ethylene biosynthesis pathway, it enables researchers to induce ethylene production and study its effects on fruit ripening, flower wilting, leaf abscission, and senescence. In agriculture, it is applied to promote uniform ripening in climacteric fruits and to manipulate post-harvest physiology for extending shelf life. Additionally, in pharmaceutical and crop improvement research, ACC is utilized to explore ethylene-mediated stress responses, aiding the development of stress-tolerant plant varieties.