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Thomas S.C. Li

Siberian ginseng [Eleutherococcus senticosus (Rupr. ex. Maxim.) Maxim] is currently a popular medicinal plant in Eurasia and North America. It has been used by the Chinese for over 2000 years. Recently, imported products of this plant have become available in North America, with a market share of 3.1% of the medicinal herbal industry. Siberian ginseng is harvested from its natural habitat in Russia and northeast China. Overharvesting has resulted in this popular herb approaching endangered species status. Cultivation is the only way to avoid its extinction, and to ensure the correct identity. Siberian ginseng is not a true ginseng (Panax quinquefolium L. or P. ginseng C.A. Meyer), but it has its own bioactive ingredients with unique and proven medicinal values. However, standardization and quality control of the active ingredients in the marketed products, which are mainly imported from China, are needed to avoid mislabeling or adulteration with other herbs.

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Thomas S.C. Li

Echinacea species, a popular medicinal herb throughout the world, have been used by indigenous Americans for hundreds of years as an effective immunostimulant. The cultivated acreage in the United States and Canada is increasing because of the great demand for Echinacea products. Better cultural methods and standardization and quality control of the value-added products are needed to increase the confidence of growers, producers, and consumers in this promising medicinal herb. Echinacea can be propagated from seed, crown division, and root sections. Seed stratification for 4 to 6 weeks at 34 to 40 °F (1 to 4 °C) before planting can improve germination. Echinacea thrives under cultivation in moderately rich and well-drained loam or sandy loam soil with regular irrigation and weed control. Roots are harvested in the fall after 3 to 4 years of cultivation. The best stage to harvest flowers has yet to be determined. Leaves are a source of valuable active ingredients, but no information is available in the literature on leaf harvesting. Active ingredients in Echinacea include polysaccharides, flavonoids, caffeic acid derivatives, essential oils, polyacetylenes, and alkylamides.

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Thomas S.C. Li

The ginseng industry has expanded rapidly in recent years. Asian and American ginseng are cultivated around the world. Ginseng products in various forms are increasingly popular, and its consumers are no longer limited to Asians. More knowledge is needed about the horticultural characteristics, cultural methods, disease control, drying and storage procedures, and technology for value-added products. Once-secretive information about ginseng and its culture is gradually becoming available, especially from the orient. Growers and researchers are eager to know more about Asian and American species of this high-value crop.

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Thomas S.C. Li and Doug Wardle

The effect of harvest period on fresh and dry leaf and root weights and ginsenoside contents of 2-, 3-, and 4-year-old american ginseng (Panax quinquefolium) plants was investigated. Ginseng plants harvested once every 4 weeks from the end of June through September had the highest and lowest fresh and dry leaf weights in June and September, respectively. The trend was reversed in roots, except for 3-year-old roots that exhibited maximum weight at the end of August. Total ginsenoside contents in leaves of 3- and 4-year-old plants increased with the growing season until the end of August, but in 2-year-old plants it increased until the end of September. Total ginsenoside contents in roots peaked at the end of June for 3- and 4-year-old plants.

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Thomas S.C. Li and G. Mazza

Four-year-old American ginseng (Panax quinquefolium L.) plants and soil samples were collected from nine ginseng gardens. Soil and leaf mineral contents were determined and six major ginsenosides, Rb1, Rb2, Rc, Rd, Re, and Rg1, were extracted from leaves and roots and quantified by high-performance liquid chromatography (HPLC). Correlation coefficients were more significant for soil nutrient levels vs. ginsenoside contents of leaves than of roots, suggesting that soil nutrient levels may play a major role in the synthesis of leaf ginsenosides. Minor elements in the leaf were also better correlated with ginsenoside contents of the root than that of the leaf. Iron content in the leaves exhibited highly significant correlations with the levels of Rb1, Rb2, Rc, and Rd, but calcium and copper contents were negatively correlated with Rg1 in the roots.

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Thomas S.C. Li and Douglas A. Wardle

The influence of seed treatments and planting depth on the percentage of seed emergence of Hippophae rhamnoides L. `Indian-Summer', H. tibetana Schlecht., H. neurocarpa Liu & He, H. salicifolia D. Don, and H. rhamnoides subsp. rhamnoides, sinensis, turkestanica, and mongolica were studied. Surface seeding had higher percentages of seed emergence and more rapid completion of emergence compared to a 1- or 2-cm (0.4- or 0.8-inch) seeding depth. Seeds soaked in water or potassium nitrate solution at room temperature emerged in higher percentages. Average plant height of the eight species and subspecies varied significantly at the end of first growing season.

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Thomas S.C. Li and W.R. Schroeder

Sea buckthorn (Hippophae rhamnoides L.) is a multipurpose, hardy, deciduous shrub, an ideal plant for soil erosion control, land reclamation, wildlife habitat enhancement, and farmstead protection. It has high nutritional and medicinal values for humans. The majority of sea buckthorn research has been conducted in Asia and Europe. It is a promising new crop for North America, and recently it has attracted considerable attention by researchers, producers, and industry.

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Thomas S.C. Li, K.E. Bedford and P.L. Sholberg

Traditionally, American ginseng (Panax quinquefolium L.) seeds are stratified for 18 to 22 months, before seeding, in a sandbox buried outdoors in late August or early September. Uncontrolled fluctuating temperature and moisture levels and the presence of pathogenic organisms in the seed box can cause seeds to sprout prematurely, rot, dry out and die. A study was initiated to shorten the lengthy stratification period, and to increase seed viability and percentage of germination by stratifying seeds indoors under a controlled environment. Seeds were subjected to various periods of warm [15 or 20 °C (59 or 68 °F)] and cold [2 °C (35.6 °F)] temperature stratification regimes in growth chambers. Embryo growth and viability, and seed moisture content were tested periodically during stratification. The best warm regime for embryo development, seed viability and germination after subsequent cold treatment was 15 °C (59 °F). The first “split” seeds, indicating incipient germination, were observed after 3 months of warm [15 °C (59 °F)] and 4 months of cold [2 °C (35.6 °F)] treatment, when average embryo length reached 6 mm (0.24 inch). Greenhouse germination of stratified seeds was as high as 80%. The results from this study indicate that good germination is possible when ginseng seeds are stratified indoors under a controlled environment and seeds can be made to germinate at any time of the year.