A field trials-based study reveals the effects of chlormequat chloride on the quality of medicinal plant Salvia miltiorrhiza Bge. (Lamiaceae) in practical cultivation

The application of some specific plant growth regulators in the cultivation of herb medicines for yield promotion is a widespread phenomenon at present. But most of these agrochemical uses in medicinal plants are without effect verification and are illegal according to related regulations, thus it is necessary to conduct studies about the effect evaluation of these plant growth regulators on medicinal plants in actual production conditions. In this study, according to a preliminary investigation that chlormequat chloride (CCC) is widely used in the cultivation of the common herb Salvia miltiorrhiza, the effects of CCC on the quality of S. miltiorrhiza were comprehensively evaluated with both metabolomics-based UPLC/Q-TOF MS method and multi-component quantitative analysis based on samples from two years field trials. A global chemical constituent identification of S. miltiorrhiza was firstly carried out and consequently 47 tanshinones and 22 phenolics were identified or tentatively identified from the UPLC/Q-TOF MS data. Then, both the qualitative multivariate statistical analysis and quantitative determinations of major active components in S. miltiorrhiza samples that were treated with different dosages of CCC revealed that the application of CCC in S. miltiorrhiza cultivation is likely to count against the herbal quality and mainly manifested as the significant decrease of tanshinones content. Above all, this work provides a beneficial case for the recognition of the blind use of plant growth regulators in herb medicines for yield improvement and indicated that the use of PGRs in medicinal plant cultivation should be more cautious, and several further study points based on this work were discussed.