ABSTRACT
Objective To study the process of the root development of Codonopsis pilosula as well as theaccumulatinglocationsofthemainmedicinalcompositionandstoragenutritionintheroot. MethodsThe development process of the roots was studied by paraffin section methods. Storage nutrition was loca-lized by PAS reaction and Sudan Ⅲ reaction. The medicinal composition of C. pilosula, terpene and steroid were stained with mix reagent of 5% vanillin-acetic acid and perchloric acid. Results The development process of the root is shown as four stages: promeristem, primary meristem, primary structure, and secondary growth. Abundant laticifers exist in mature root and the prime laticifers could be found in phloem as early as the first vessel of primary xylem appears. Then, the laticifers exist in phloem at all time. Starch granule accumulated in mature root as reserved substance. Terpene and steroid accumulated in parenchyma and laticifer. Conclusion Parenchyma and laticifer in the roots of C. pilosula are the main parts of the roots to store medicinal composition and storage nutrition.