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John T.A. Proctor, David C. Percival, and Dean Louttit

Manual removal of inflorescences from mature (3- and 4-year-old) American ginseng plants (Panax quinquefolium L.) at commercial timing (early July, ≈25% flowers open) increased root yield at harvest. Consecutive inflorescence removal for 2 years (third and fourth) increased yield 55.6%. Inflorescence removal in 4-year-old plants increased yield by 34.7% compared with 26.1% in 3-year-old plants. Analysis showed that the largest portion of roots (≈40%) was in the medium category (10-20 g), and inflorescence removal did not influence root size distribution. Root yield for 3-year-old plants increased quadratically with plant density, with plants lacking inflorescences having an estimated yield increase of 25%. Maximum yields of 2.4 kg·m-2 for deflowered plants were achieved at a plant density of 170 plants/m2. To maximize ginseng root yield, all plants except those needed to provide seed for future plantings should have inflorescences removed.

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C.L. Boehm, H.C. Harrison, G. Jung, and J. Nienhuis

Genetic differences among eleven cultivated and eight wild-type populations of North American ginseng (Panax quinquefolium L.) and four cultivated populations of South Korean ginseng (P. ginseng C.A. Meyer) were estimated using RAPD markers. Cultivated P. ginseng population samples were collected from four regions of S. Korea. Cultivated P. quinquefolium population samples were collected from three regions in North America: Wisconsin, the Southeastern Appalachian region of the United States, and Canada. Wild-type P. quinquefolium was collected from three states in the United States: Pennsylvania, Tennessee, and Wisconsin. Evaluation of germplasm with 10 decamer primers resulted in 100 polymorphic bands. Genetic differences among populations indicate heterogeneity. The genetic distance among individuals was estimated using the ratio of discordant bands to total bands scored. Multidimensional scaling of the relationship matrix showed independent clusters corresponding to the distinction of species, geographical region, and wild versus cultivated types. The integrity of the clusters was confirmed using pooled chi-square tests for fragment homogeneity.

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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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Wansang Lim, Kenneth W. Mudge, and Jin Wook Lee

We determined the effect of moderate water stress on the growth of american ginseng (Panax quinquefolium), and on concentrations of six major ginsenosides (Rg1, Re, Rb1, Rc, Rb2, and Rd). Two-year-old “rootlets” (dormant rhizome and storage root) were cultivated in pots, in a cool greenhouse (18.3 ± 2 °C). Pots were watered either every 5 days (control) or every 10 days (stress), repeatedly for 8 days. Soil volumetric water content was measured during the last 10 days of the experiment for both treatments. Leaf water potential, measured on the last day of the experiment, was -0.43 MPa for the control and -0.83 MPa for the stress treatment. Drought stress did not affect above-ground shoot or root dry weight. Initial rootlet fresh weight (covariate) had a significant effect on the concentration of ginsenosides Re, Rb1, Rc, and Rb2. Drought stress increased the concentration of ginsenosides Re, Rb1, and total ginsenoside concentration.

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L.X. Zhang, W.C. Chang, Y.J. Wei, L. Liu, and Y.P. Wang

Cryopreservation of pollen from two ginseng species —Panax ginseng L. and P. quinquefolium L.—was studied. Freezing anthers that served as pollen carriers to –40C before liquid N storage affected pollen viability little after liquid N storage. Anther moisture content affected pollen viability significantly when stored in liquid N. The ideal anther moisture content to carry pollen for liquid N storage was 32% to 26% for P. ginseng and 27% to 17% for P. quinquefolium. Viability of pollen from P. quinquefolium anthers with 25.3% moisture content changed little after 11 months of liquid N storage.

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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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T.R. Konsler

Abstract

Dormant one-year-old roots of American ginseng (Panax quinquefolium L.) were exposed to a range of stratification temperatures and times to define limits for these parameters and to quantify their effect on terminating rest when placed in a growing environment. Effective storage temperatures tested ranged from 0° to 9°C. A low percentage of roots produced tops with as few as 30 days of stratification; however, 60 to 90 days were required for 100% emergence. The number of days to emergence, after planting, decreased with increased time in stratification through the maximum storage time of 120 days. The number of days of dormancy (days in stratification + days to emergence) averaged 126 and was relatively constant over the range of effective temperatures and periods of stratification. The minimum predicted period of dormancy was 116 days and was associated with a derived 70 days in storage (1680 hr) at 3.1°. Root growth rate, after emergence, was greatest following 105 days of stratification.

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Jin Wook Lee, Kenneth W. Mudge, and Joseph Lardner

American ginseng (Panax quinquefolium L.) contains pharmacologically active secondary compounds known as ginsenosides, which have been shown to be affected by both genetic and environmental factors. In this greenhouse experiment, we tested the hypothesis that ginsenosides would behave as “stress metabolites” and be associated with osmoregulation in response to drought stress. Two year-old seedlings, grown in 5-inch pots, were well watered for 40 days prior to the initiation of treatments. Plants in the drought stress treatment were watered every 20 days while the controls were watered every 10 days, and the experiment was terminated after 4 and 8 dry down cycles (80 days), respectively. Predawn leaf water potential and relative water content (RWC) of drought-stressed plants during a typical dry down cycle were lower than control plants. The diameter and weight of primary storage roots were decreased in the stressed treatment. The length of the main storage root and the longest secondary (fibrous) root were significantly increased by the drought stress treatment. Leaf chlorophyll content of drought-stressed plants was lower than controls. The osmotic potential of the drought-stressed ginseng was not lower than the control, indicating that ginsenoside is not involved in osmoregulation in response to drought stress. Furthermore, ginsenosides Rb1 and Rd, and total ginsenosides were significantly lower in primary roots of drought-stressed plants compared to control plants.

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Jin Wook Lee and Kenneth W. Mudge

In the Northeast, wild American ginseng (Panax quinquefolium L.) is typically found growing in the dense shade provided by deciduous hardwood tree species such as a sugar maple, in slightly acidic soils with relatively high calcium content. Woods cultivated ginseng is often grown in forest farming agroforestry systems under similar conditions. Supplemental calcium by soil incorporation of gypsum (CaSO4·2H2O) is often recommended for woods cultivated ginseng. The objective of this study was to investigate the effects of this practice on soil chemical properties, plant growth and quality of American ginseng. In a greenhouse pot culture experiment, 2-year-old seedlings were treated with 0, 2, 4, 8, or 16 Mt·ha–1 gypsum and grown for 12 weeks. Gypsum application decreased soil pH slightly, elevated soil electrical conductivity and increased available soil Ca and sulfate concentrations. Tissue calcium concentration was increased with by gypsum treatment, but shoot and root growth was reduced. HPLC analysis of root ginsenosides revealed that Re, Rb1, Rc, and Rb2, PT ginsenoside (sum of ginsenoside Rb1, Rc, Rb2, and Rd) and total ginsenoside concentration increased by gypsum soil amendment.

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Jin Wook Lee*, Kenneth W. Mudge, Wansang Lim, and Joseph Lardner

Woods cultivation of North American ginseng (Panax quinquefolium L.) can generate income for forest land owners and decrease collection pressure on wild populations of this increasingly scarce forest herb. For woods cultivation, supplemental calcium by soil application of gypsum (CaSO4 2H2 O) is often recommended, but the effects of this practice on soil characteristics, plant growth and quality of American ginseng are not well characterized. In a greenhouse pot culture experiment, 3-year-old seedlings were treated with 0, 1, 2, 3, or 4 Mt/ha gypsum and grown for 12 weeks. Gypsum application decreased soil pH slightly and elevated soil electrical conductivity and available soil calcium. Tissue levels of calcium were not affected by gypsum treatment but a significant increase in both shoot and root dry weight occurred. Total ginsenosides, which are the pharmacologically active components of ginseng, were increased slightly in roots but not in shoots of plants treated with 4 Mt/ha gypsum. Rb1, the most abundant ginsenoside in roots, was elevated in roots of plants treated with 3 Mt/ha gypsum. Ginsenoside Rg1 was elevated in shoots of plants treated with 2 Mt/ha gypsum. Regardless of gypsum treatment, qualitative differences (relative concentrations of different ginsenosides) between roots and shoots were observed.