Seasonal Trends and Plant Density Effects on Cichoric Acid in Echinacea purpurea (L.) Moench

Abstract

ABSTRACT Field studies were used to identify the effects of plant density and seasonal trends on cichoric acid in Echinacea purpurea roots, foliage, and flowers. A spoke-wheel planting design was used to determine optimum plant density. Very dense plant populations (over 15 plants per m2) resulted in high biomass production, but cichoric acid concentration in the plant tissue was reduced. A density of 9 to 10 plants/ m2 maintained cichoric acid in the root near 12 mg/g with root dry matter yields of approximately 2500 kg/ha in the second year. Biweekly sampling of roots, foliage, and flowers from late June through mid-October showed that cichoric acid declined in all tissues during the growing season, but most rapidly in over-mature flowers. The highest concentration of cichoric acid was detected in immature flowers, but the greatest amount of cichoric acid per flower was in fully developed flowers before petal senescence. The total amount of cichoric acid per root was highest before flowering, but peaked in the plant top in early to mid-August in western Montana. Removal of 50 percent of the foliage in mid-August of the second year of growth resulted in a small but significant reduction in the yield of roots harvested that fall, but removal of only the flowers had no effect. The root crown was higher in cichoric acid than the thick (> 1 mm diameter) or fine roots. Drying of foliage rapidly in a forced-air dryer at 32°C or slowly in a shaded greenhouse did not differ in cichoric acid concentration in the tissue.