Regulatory Effects of Chlormequat Chloride on the Yield and Chemical Composition of Angelica sinensis Radix

Chlormequat chloride (CCC), as a commonly used plant growth regulator in the production of rhizomatous medicinal herbs, can effectively control the bolting phenomenon in Angelica sinensis, significantly increasing the yield of underground rhizomes (medicinal part). However, its specific effects on the intrinsic quality of Angelica sinensis, especially medicinal components, require further investigation. The objective of this study is to conduct a thorough examination of CCC residue and its influence on the yield and medicinal components of Angelica sinensis. By spraying different concentrations of CCC on Angelica sinensis, we systematically monitored the final yield of Angelica sinensis Radix (ASR) in each treatment group and the residual concentration of CCC in ASR. Using UPLC-QTOF-MS technology, we conducted an in-depth analysis of the metabolic profile of ASR. Subsequently, UFLC-MS/MS was employed to accurately quantify the changes in the content of nine key active components in ASR. The results of this study indicate that the application of CCC significantly improves the yield of ASR, with the best effect observed at 0.1 g/L, resulting in a yield increase of 24.8%. Meanwhile, the residual amount of CCC in ASR is positively correlated with the application concentration, with the residual levels as high as 7.12 mg/kg in the high-concentration treatment group. Metabolomic analysis preliminarily identified 21 chemical components in ASR, including four organic acids and 13 phthalides. It is worth noting that the quantitative analysis results indicate significant changes in active components such as butylphthalide, Z-ligustilide, and ferulic acid after the application of CCC. Specifically, high-concentration CCC significantly increased the content of butylphthalide and levistolide A, while low-concentration CCC significantly promoted the accumulation of coniferyl ferulate and senkyunolide A, accompanied by a significant decrease in Z-ligustilide and ferulic acidy. In conclusion, while CCC use can increase yield, the associated increase in residues and imbalanced composition ratios may threaten the quality and safety of ASR. Therefore, it is crucial to control the amount of CCC used rationally to balance yield enhancement and quality assurance.