Effects of growing methods and plant age on the yield, and on the content of flavonoids and phenolic acids in Echinacea purpurea (L.) Moench

The effect of three different growing methods, and plant age on the yield of purple coneflower (Echinacea purpurea L.) Moench., Asteraceae are described. The weight of fresh and dry mass of rhizomes increased significantly with the age of the plants. Independently of the age, the highest yield of rhizomes (1779 g/m2 FW - 589 g/m2 DW in the third year) was found in the plants grown from root cuttings and the smallest (385 g/m2 FW - 108 g/m2 DW in the third year) from seeds sown directly into the soil. A similar dependence was obtained in the yield of flower heads. No relation was noticed between the growing method and the flavonoids and polyphenol acids contents neither in the flower heads nor in the rhizomes. The polyphenol acids content was slightly higher in the flower heads (2.85% in the third year) than in the rhizomes (2.22% in the third year). The results demonstrate that the experimental factors can stimulate increased yield of rhizomes and flower heads of E. purpurea.