Effects of Growth Regulators and Sowing Densities in American Ginseng (Panax quinquefolius L.) Culture

Plant growth regulators as well as sowing density are one of the most important factors affecting yield and metabolite formation of medicinal plants. A three-year field experiment examining the effects of two sowing densities (15 × 3 cm and 15 × 5 cm) and foliar application of growth regulators on root yield and ginsenoside content at American ginseng (Panax quinuefolius L.) was conducted. In mid-June of the 1st and 2nd year of growth, various growth regulators were evaluated against a control spray of water only: B-Nine 85 SP, Pommit Extra 110 SL and Arbostim 10 SL. The growth regulators tested significantly affected plant population, root weight and accumulation of root ginsenosides. Foliar applications of Pommit Extra and B-Nine during the first and second year, especially at lower densities, increased root weight, whereas Arbostim decreased them. Foliar application of all growth regulators tested (particularly of Pommit Extra and Arbostim) increased total root ginsenoside content after three year growth. Plant grown at higher densities (15 × 3 cm) contained relatively higher amounts of ginsenosides. Spraying American ginseng plants with Pommit Extra or B-Nine significantly increase yield of roots and ginsenosides content.