Objective This study aimed to investigate the effects of foliar application of plant growth regulators (PGRs) at different concentrations on physiological metabolism and quality formation in ginger, providing a theoretical basis for rational PGR use in ginger cultivation.

Method Ginger plants were treated with foliar sprays of 2,4-dichlorophenoxyacetic acid (2,4-D), 6-benzylaminopurine (6-BA), salicylic acid (SA), or paclobutrazol (PP₃₃₃) at various concentrations. Measurements were taken for chlorophyll content, soluble sugar content, soluble protein content, and antioxidant enzyme (CAT, POD) activities in the leaves, as well as curcumin and gingerol content in the rhizomes.

Result PGR application effectively promoted the accumulation of photosynthetic products. The most significant promotion of chlorophyll synthesis was observed with 75 mg/L 2,4-D, 100 mg/L 6-BA, and 500 mg/L paclobutrazol. PGRs significantly influenced the antioxidant enzyme system: 2,4-D activated POD and CAT activities at low concentrations but inhibited them at high concentrations, whereas the other three regulators generally suppressed CAT activity but enhanced POD activity. All four PGR treatments consistently inhibited curcumin accumulation while significantly promoting gingerols synthesis. The optimal concentrations for enhancing gingerols content were 25 mg/L 2,4-D, 100 mg/L 6-BA, 75 mg/L salicylic acid, and 200 mg/L paclobutrazol, respectively.

Conclusion Foliar application of 2,4-D, 6-BA, salicylic acid, and paclobutrazol can significantly influence ginger growth and quality by modulating its physiological metabolic processes.