The study of physiological response mechanism and metabolomics on B. chinensis under drought

Abstract Background B. chinensis is an important medicinal plant and garden plant in China, and drought is one of the factors limiting the growth of B. chinensis, so it has become a research hotspot to investigate the physiological response mechanism of B. chinensis to drought. Results In this study, we investigated the physiological and biochemical response mechanisms of the root system of B. chinensis using B. chinensis seedlings as experimental materials, and root metabolomics were analyzed to investigate the response mechanisms of this plant under drought stress. The results showed that: (1) with the prolongation of drought stress, the relative water content gradually decreased, the diameter of root, the diameter of the mid-column, the thickness of the cortex, and the diameter of the xylem all showed an upward trend and then a downward trend, the root activity gradually declined, the root structure was impaired, the cortex was not arranged and ruptured. (2) With the prolongation of drought stress, the cell membrane function was impaired, the relative conductivity and malondialdehyde content of roots tended to increase, the content of osmoregulatory substances such as soluble proteins and free proline also accumulated in large quantities in the roots, and the content of hydrogen peroxide and superoxide anion gradually increased. (3) A total of 656 differential metabolites were screened in the root system of B. chinensis under drought stress. In addition, KEGG enrichment analysis revealed that the metabolic pathways involved in the differential metabolites were mainly glycerophospholipid metabolism, sphingolipid metabolism, amino acid metabolism. Among them, the differences in flavonoid biosynthesis varied greatly, suggesting that flavonoids play an important role in the response to drought stress in B. chinensis. Conclusions This study reveals the defense response mechanism of B. chinensis under drought, with a view to laying a theoretical foundation for physiological and metabolic studies revealing B. chinensis response to drought stress.