[Spatiotemporal accumulation patterns of pharmacodynamic components in Taraxacum officinale and their response to...

This study systematically investigated the spatiotemporal accumulation characteristics of pharmacodynamic components in Taraxacum officinale and their response mechanisms to drought stress. The objectives were to elucidate the plant's growth traits and quality formation patterns, so as to guide its standardized cultivation and ensure a stable supply of high-quality medicinal materials. The contents of seven pharmacodynamic components were determined in different organs(leaf, root, flower, and scape) of flowering plants to pinpoint their primary accumulation sites. A pot experiment was conducted with samples collected at various time points(40-110 days) to measure growth indicators and pharmacodynamic component contents, thereby determining the peak accumulation period for biomass and pharmacodynamic components. Drought stress treatments were applied by regulating soil moisture levels(90%, 80%, 70%, and 60%), during which plant growth indicators, physiological and biochemical indicators, as well as pharmacodynamic component contents were assessed. The results showed that leaves were the primary accumulation site for the pharmacodynamic components. Both biomass and the contents of multiple key pharmacodynamic components exhibited an initial increase followed by a decrease, peaking simultaneously at the 90th day. Drought stress significantly inhibited plant growth in T. officinale, induced the accumulation of proline and soluble sugars, and reduced the activities of peroxidase and catalase as well as the malondialdehyde content. Mild drought stress(80% soil moisture) increased the contents of certain phenolic acids and flavonoids, whereas severe drought stress(60% soil moisture) caused a significant decline in the content of most pharmacodynamic components. In conclusion, the pharmacodynamic components of T. officinale predominantly accumulate in the leaves and reach their peak levels concurrently with biomass(at the 90th day), highlighting the critical importance of timely harvesting for ensuring both yield and quality. Mild drought stress can enhance the content of pharmacodynamic components to varying degrees; however, severe drought stress leads to substantial reductions in both yield and quality.