Environmental Impacts of Plant Growth Regulators in Modern Agriculture: Advances, Risks, and Sustainable Perspectives

Plant growth regulators (PGRs) are extensively used in modern agriculture to modify plant developmental processes, enhance productivity, and improve crop quality under increasingly variable environmental conditions. While their agronomic benefits are well established, growing attention has been directed toward understanding their broader environmental implications. In this current review, we analyze recent research published over the last five years to evaluate the environmental behavior and ecological impacts of widely used natural and synthetic plant growth regulators. Particular emphasis is placed on their persistence and mobility in soil and water, their interactions with soil microbial communities, and their effects on non-target terrestrial and aquatic organisms. Recent advances in analytical detection and ecotoxicological assessment have revealed that several PGRs, despite being applied at low doses, may exhibit prolonged environmental residence and subtle biological effects, particularly following repeated applications. Alterations in soil enzyme activity, shifts in microbial community structure, and growth disturbances in non-target plants and aquatic primary producers have been increasingly reported. The review also discusses emerging strategies aimed at reducing environmental risks, including precision application technologies, the development of biodegradable regulators, and improved regulatory frameworks. Overall, these findings highlight the need for integrated risk assessment approaches and long-term field studies to support the sustainable use of plant growth regulators in agroecosystems.