Embryo Growth and Germination of American Ginseng Seed in Response to Stratification Temperatures

Embryos of American ginseng ( Panax quinquifolius L.) seeds stratified 570 days at 0° or 5°C did not increase in size, whereas embryos of seeds stratified 570 days at 20° grew to a length of 2.5 mm. Embryos of seeds stratified at 5° for 120 days, treated with 1000 ppm gibberellic acid (GA), then transferred to 20° grew to the same length as those held at a constant 20°. None of the GA treated seeds germinated. However, seeds stratified outdoors and those provided 5° for 120 days, 20° for 300 days, and then held at 5°C germinated after 540 days. The embryos of these latter treatments had similar growth patterns. Growth of the cotyledons paralleled the growth of the entire embryo. Cool-warm-cool stratification patterns are necessary for efficacious germination of American ginseng seeds.