Echinacea fruits: Phytochemical localization and germination in four Echinacea species

Echinacea has received extensive research attention, yet relatively little is known about the fruits (cypselae) of this economically important genus. The goal of this study was to investigate and compare the cypselae of four Echinacea species, E. purpurea, E. angustifolia, E. pallida, and E. paradoxa, with respect to chemistry and germination. The phytochemical content of various fruit fractions was analyzed by HPLC-DAD, identifying several alkylamides and caffeic acid derivatives of medicinal value in all tissues. Alkylamides were most concentrated in the perianth and glands while phenolics were generally enriched within the seed. Germination studies of intact cypselae and de-coated seeds demonstrate that the influence of cypsela coatings on germination depends on growth environment. Removal of the perianth and pericarp resulted in decreased germination in soil but significantly improved germination of seeds of all species when sown in sterile agar medium. In contrast, a higher percentage of intact cypselae of E. purpurea, E. angustifolia, and E. pallida germinated in soil than in sterile agar. These results suggest an ecophysiological role for phytochemicals in seed germination and will inform the cultivation and breeding of less common Echinacea species as well as the development of new products from currently unused plant material.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author