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Abstract

Excised embryos and explants from 2-week-old and 4-month-old seedlings of Mugo pine (Pinus mugo Turra var. mugo) were cultured in vitro on nutrient media containing BA and NAA. Shoot development on intact embryos occurred primarily via adventitious bud formation that was greatest On a medium containing 44.4 μM BA and 0.05 μM NAA. Subsequent shoot elongation was improved by transferring buds to a growth regulator-free medium containing 1 g/liter activated charcoal (AC). After removal from culture, shoots rooted in response to treatment with 0.8% IBA. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA); 1-naphthaleneacetic acid (NAA); and 1H-indole-3-butanoic acid (IBA).

Open Access

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.

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Variation in ginsenoside content was investigated as a function of population/genotype, plant organ, and age using four geographically isolated wild populations and one landrace population of american ginseng (Panax quinquefolius L.). The contents of individual and total ginsenosides were affected by the main and two-way interactions between population, organ, and age. Ginsenoside Re was not detected in roots of the wild population plants but was found in leaves and in both organs of the landrace population. A positive relationship between root age and total root ginsenosides was detected in two wild populations. Individual root ginsenosides were highly correlated with certain leaf ginsenosides in wild populations rather than in landrace populations. Therefore, the results suggest that certain leaf ginsenosides would be applied for potential biomarkers to estimate individual root ginsenosides. Principal component analysis (PCA) scores plot indicates that all wild populations were segregated from the single landrace population. However, cluster analysis indicates that differences existed between organs, and between the wild and landrace populations. Overall, the result suggests that the variation of individual and total ginsenoside contents would be influenced by a combination of population, plant organ, and root age.

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In vitro asymbiotic seed germination, subculture, and outplanting of orchids is presented as a laboratory exercise suitable for students of plant propagation or tissue culture. Dendrobium antennatum (Lindley), Phalaenopsis (Blume) white hybrid, or both, are used in this exercise because they flower predictably in the greenhouse, are reliable for seed production, and germinate and grow rapidly in vitro. The exercises can be used to instruct students in the skills involved in orchid seed sterilization, sowing, and culture, as well as instruct students in the unique features of orchid reproductive biology and symbiosis. A schedule is suggested for stock plant flower pollination, capsule harvest, seed sowing, and seedling subculture so that the necessary plant material is available for students to sow, subculture, and outplant seedlings during a single laboratory session.

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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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The role of cooperative extension in providing information to amateur and professional horticulturists is being profoundly altered by the availability of vast amounts of horticultural resources on the World Wide Web and other electronic media. Advances in computer-related instructional technologies including the Internet, have coincided with, and to some extent triggered, a burgeoning demand for non-traditional continuing education in practically all fields of knowledge, including landscape horticulture. Although there are numerous Web sites offering a wide range of gardening and related information, there are relatively few opportunities for structured learning in the form of on-line distance learning courses or instructional modules. In Fall 1999, we conducted a survey of the membership of the New York State Nursery/Landscape Association to determine priority-training needs that might be met by computer-mediated distance learning. One-hundred-seven companies, representing horticulture-based businesses throughout New York State, completed the surveys. Results from the survey indicated that 83% of those responding were interested in taking one or more computer-based distance learning course(s), that 67% were willing to provide financial support for continuing education of their employees, and that 95% have access to a personal computer. We have also collected data indicating subject matter preferences, interest in full-course and short-course offerings, levels of computer and Internet experience, and more. It is apparent from the findings in this study that the cooperative extension has a great opportunity to use the World Wide Web as a component of its role as an information provider. This research will contribute to designing effective approaches for teaching hands-on horticultural skills at a distance, thereby expanding the cooperative extension's ability to reach its intended audiences.

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Rockwool plugs were placed in Magenta G-7 boxes (Sigma) and then autoclaved at 121°C for 20 min. Fifty milliliters of cool autoclaved liquid medium was poured into Magenta G-7 boxes in aseptic conditions before microcuttings of Amelanchier, Cercis canadensis, cherry, and apple were transferred. Murashige and Skoog medium (MS, M-5519, Sigma) containing 30 g·L–1 sucrose, and with/out 1 ppm of NAA, pH 5.5 were used in all experiments. All cultures were incubated at 23 ± 1°C under a 16-hour lighting period with a light intensity of about 4000 lux of white fluorescent light. Microcuttings of Amelanchier, Cercis, Apple, and cherry rooted in rockwool plugs in 3 weeks after transfer and were ready to be out-planted in 6 weeks. Out-planted plantlets were leached with tap water and potted in 4-inch pots with Metrolite mix, then, placed in mist bench under 50% shade for 2 weeks before taking to bench with full sun light. The survival was 100%. Conditions and growth rate of rockwool-plug-rooted plantlets were much better than those plantlets rooted in agar medium. Rockwool plug plantlets had 2–3 flushes of growth before dormancy in greenhouse and were ready to be planted in the field or garden in 8 months after out-planting. Using a rockwool plug system simplifies out-planting procedure, produces better plantlets, increases out-planting survival, and greatly shorten time needed from out-planting to field-plantable size. This system is a very useful system for difficult-to-root woody ornamentals.

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Seeds from mature seed pods of Cypripedium calceolus var. parviflorum were germinated on 1/4 MSMO (Sigma) + 100ml/l coconut water + 1% sucrose +/- 8g/l agar (pH 6.0), and with or without prechilling at 5C for 8 weeks. Protocorm with apex (stage 3) was use as an index of germination. Seeds sown on agar medium withou chilling treatment resulted in a 40% germination rate in 120 days but the germination was very uneven. Seeds germinated on agar medium with prechilling developed more synchronously with 92% germination in 60 days (ie. about 120 days after sowing). Suspension culture of seeds without prechilling resulted in 85% germination after 90 days. The synchronization of seed germination in suspension culture was intermediate between that on agar with and without prechilling. Protocorms germinated in suspension culture appeared morphologically identical to those germinated on agar medium. All stage 3 protocorms developed further on the same agar medium in darkness.

Both agar and suspension culture in media containing coconut water provided reliable seed germination methods for this orchid species.

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An instructional system involving tropical hibiscus (Hibiscus rosa-sinensis) was developed for teaching hands-on grafting skills as part of a traditional comprehensive course in plant propagation and also as part of an online grafting course. The advantages of using tropical hibiscus include the following: the absence of phenological constraints associated with seasonal changes in temperate woody species; the comparative ease of grafting hibiscus, assuring positive reinforcement of the student's learning experience; and the ease of propagating and growing hibiscus in the greenhouse for use at any time of year. The three methods included in these laboratory exercises are top wedge grafting—selected for its ease and high rate of success—T-budding, and chip budding. In addition to development of hands-on skills, the exercises are designed to teach students three of the most important requirements for successful grafting of any species, regardless of method. These requirements include cambial alignment, application of pressure between stock and scion, and avoidance of desiccation. An online rating tutorial and lab report form was developed for students to self-evaluate their grafted plants.

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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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