Panaxquinquefolium L. (American ginseng) is an herb native to North America that is now cultivated in East Asia as well. Its active compounds, ginsenosides, have been documented to exert a wide range of biological activities resulting in
The Catskill Mountains of New York are an important source of wild-collected American ginseng (Panax quinquefolium), and increasingly, of woods-cultivated ginseng. The objective of this study was to assess genetic diversity among eight different wild ginseng populations from the Catskill Mountains and to compare Catskill populations to five wild populations from other states including Kentucky, Tennessee, North Carolina, Pennsylvania, Virginia, and one cultivated population from Wisconsin. Randomly amplified polymorphic DNA markers were used to estimate the genetic difference among the 14 populations using PCR amplified nuclear DNA. Fifteen random primers were selected from a total of 64 random decamer primers by screening bulked DNA samples from the eight Catskill populations. These 15 primers were then used to compare 10 plants each from the eight Catskill populations and three to four plants each from the non-Catskill populations. The 15 primers produced 124 polymorphic bands. The genetic distance within and among populations was estimated using the ratio of discordant bands to total bands. Multidimensional scaling of the relation matrix showed separation of Catskill and non-Catskill population clusters. Significant differences between these groups was confirmed using pooled chi-square tests for fragment homogeneity. Although the eight Catskill populations differed from the non Catskill populations, there were no significant differences among the Catskill populations. This study shows that presence and absence of bands can be used as population specific markers for American ginseng. Although these results do not rule out the possibility that there may be some level of genetic differences among Catskill populations, 10 plants per population was not sufficient to establish such differences.
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.
Ginseng is an herbaceous perennial that grows in the understorey of deciduous hardwood forests and is also cultivated for its highly valued root. The primary method of propagation of ginseng is by seed which requires the breaking of dormancy by stratification, a process which takes 18–24 months. Investigation of factors controlling the growth and development of ginseng plants is a prerequisite to the development of a more efficient system of ginseng propagation. We have recently modulated the morphogenetic potential of geranium roots and stimulated de novo development of shoots and embryo-like structures which later formed whole plants using thidiazuron (TDZ). Our objective was to investigate the morphological changes in seedling and mature ginseng plants induced by TDZ, particularly in relation to root and shoot morphogenesis and economic yield. Applications of TDZ (0.22 and 2.20 ppm), either as foliar sprays or soil watering to greenhouse-grown seedlings over 18 weeks (2 weeks after sowing to 20 weeks when plants were harvested) induced similar effects. These responses included increased stem length and diameter, and shoot and root weight (economic yield). Single foliar applications of TDZ at 62.5 and 125 ppm to 3-year-old field-grown ginseng plants 3 months before harvest increased root biomass (economic yield) by 19% to 23%. Roots of TDZ-treated seedlings and 3-year-old field-grown plants developed thickened secondary roots on the upper part of the taproot. The root-like structure of these secondary roots was confirmed by histology. In addition, TDZ treatments induced adventitious buds on the shoulder of 3-year-old roots. These buds developed into shoots to give multi-stem plants following a period of dormancy, which was overcome with GA3 (gibberellic acid) treatment before planting.
Friable embryogenic callus of American ginseng (Panax quinquefolium L.) was induced from root pith on Murashige and Skoog medium supplemented with 2 mg 2,4-D and 1 mg KIN/liter. Optimal callus growth occurred on medium containing 1.5 mg dicamba/liter. Plants were regenerated on MS medium supplemented with various concentrations of plant growth regulators (PGRs); the best PGR combination was 0.5 mg IBA and 0.1 mg NAA/liter. Chemical names used: (2,4-dichlorophenoxy) acetic acid (2,4-D); 3,6-dichloro-o-anisenic acid (dicamba); 6-benzylaminopurine (BA); gibberellic acid (GA); indole-3-butyric acid (IBA); kinetin (KIN); and naphthaleneacetic acid (NAA).
The magnitude of genetic differences among and the heterogeneity within cultivated and wild American ginseng populations is unknown. Variation among individual plants from 16 geographically separated, cultivated populations and 21 geographically separated, wild populations were evaluated using RAPD markers. Cultivated populations from the midwestern U.S., the southern U.S., and Canada were examined. Wild populations from the midwestern U.S., the southern U.S., and the eastern U.S. were examined. Polymorphic bands were observed for 15 RAPD primers, which resulted in 100 scored bands. Variation was found within and among populations, indicating that the selected populations are heterogeneous with respect to RAPD markers. The genetic relationships among individual genotypes were estimated using the ratio of discordant bands to total bands scored. Multidimensional scaling of the relationship matrix showed independent clusters corresponding to the geographical and cultural origins of the populations. The integrity of the clusters were confirmed using pooled chi-squares for fragment homogeneity. Average gene diversity (Hs) was calculated for each population sample, and a one-way analysis of variance showed significant differences among populations. Overall, the results demonstrate the usefulness of the RAPD procedure for evaluating genetic relationships and comparing levels of genetic diversity among populations of American ginseng genotypes.
Soil applications of dolomitic limestone and P fertilizer before seeding American ginseng (Panax quinquefolium L.) affected root weight (RW) gain during the first 4 years of growth. At the end of each growing season, root size was greatest with the intermediate liming rate and with the high P rate. Lime resulted in positive linear responses in soil pH, K, Ca, and Mg and in root N, P, Ca, and Mg and curvilinear responses in soil Mn and Zn and in root K, Mn, and Zn. Applied P had a positive linear effect on soil Na and on root N, Ca, and Fe and a curvilinear effect on soil P and on root P and Ca. Terminal RW was positively correlated with soil pH, K, Ca, Mg, and Na and with root P, K, Ca, and Mg; RW was negatively correlated with root Mn and Zn. Regression analyses implicated only soil Ca and Na and root Mg and Zn as significant terms in prediction equations,
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.
Ginseng seedlings were inoculated with Phytopthora cactorum by dipping their roots for 5 min in a suspension of 105 zoospores/ml. Inoculated plants were repotted and grown under shade in the greenhouse. In various experiments, fungicides were applied 1 week before inoculation, at the time of inoculation, 2 days after inoculation, or a combination of the first two of these. Treatments included fosetyl-Al applied as a foliar spray until run-off at a concentration of 2.5, 5.0, or 10 g a.i./liter of water or as a soil drench containing 0.25, 0.5, or 1.0 g a.i./100 ml water per plant and metalaxyl applied as a soil drench containing 5 or 10 mg a.i./100 ml of water per plant. The treatments with fosetyl-Al as a spray did not reduce root rot ratings, but fosetyl-Al applied as a drench significantly reduced root rot ratings at all three concentrations when applied at inoculation. The best control was achieved using metalaxyl at either 5 or 10 mg a.i./plant applied either at inoculation or both 1 week before inoculation and at inoculation.
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.