6-Benzylaminopurine as a Multifaceted “Architect” Reshaping Plant from Morphogenesis, Stress Resistance, and Molecular Signaling

Amid growing abiotic stress and food security demands, crops face growth inhibition, yield reduction, and premature aging. As a synthetic cytokinin analog, 6-benzylaminopurine (6-BA) exerts effects beyond promoting cell division. This review proposes that the core function of 6-BA lies in achieving systematic reshaping of plants from morphogenesis to stress adaptation by regulating phytohormone interactions, carbon source/secondary metabolism, and gene expression networks. However, existing studies on 6-BA are scattered and lack systematic integration of its physiological functions, molecular mechanisms, application efficacy, and residue risks. This review comprehensively summarizes the physiological functions of 6-BA and its molecular interactions with endogenous substances. Furthermore, we also emphasized the residual risks associated with the overuse of 6-BA and evaluated trace-level detection techniques. This review provides a comprehensive theoretical basis for scientifically applying 6-BA in agriculture, offering a reference for achieving a balance between crop high-yield objectives, food safety, and ecological sustainability.