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Linda J. Walker, R.B. Rogers, and M.A.L. Smith

In vitro cell cultures of huckleberry and bilberry are sources of phytochemicals for use as food colorants and bioactive chemopreventives. Shoot cultures provide a convenient, presterile source of explants for production of callus rich in extractable pigments or other chemicals. Efficient callus formation only occurs with good-quality shoots. In this study, liquid and gelled support systems were compared in terms of their effect on shoot growth. Gellan gum-based support resulted in excellent shoot proliferation and suitable shoot length for huckleberry cultures, whereas bilberry performed slightly better on agar and agar/gellan gum support. Bilberry had a more-rapid growth rate than huckleberry. Hyperhydricity was found with the use of rafts for both species. These shoot cultures have been used as vegetative explants for callus, and have produced vivid anthocyanins in solution cultures.

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Rita M. Moraes-Cerdeira, Jeffrey V. Krans, James D. McChesney, Ana M.S. Pereira, and Suzelei C. Franca

Cotton fibers were tested as a substitute for agar in tissue culture. The cost of agar has prompted us to search for an alternative more economical medium support. Effectiveness as a medium support was evaluated in terms of callus maintenance and shoot organogenesis using Artemisia, Agrostis, and Taxus. Taxus and Agrostis calli cultivated on liquid media with cotton fiber as medium support (25 ml of medium per gram of cotton) grew better than calli on agar (0.8% w/v). There were no significant differences in shoot organogenesis of Artemisia and Agrostis grown in 25 ml of medium per gram of cotton from those grown in agar medium.

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Michael Marcotrigiano and Susan P. McGlew

A two-stage micropropagation system was devised for cranberries (Vaccinium macrocarpon Ait.). Shoot-tip explants taken from four cultivars of greenhouse-grown plants were placed on media composed of Anderson's major salts, Murashige and Skoog's (MS) minor salts and organics, plus various concentrations of 2iP, IBA, and GA3. In other experiments, explant source, salt formulations for media, and rooting treatments were studied. Optimal multiplication and shoot quality occurred when nodal explants taken from greenhouse-grown or micropropagated plants were placed on medium containing 150 μm 2iP, 1.0 μm IBA, and no GA3. Histological examination revealed that the initial response of nodes to culture is axillary bud proliferation, but adventitious shoot formation occurred after 4 to 6 weeks. Cultures that contained only axillary shoots were not evident unless low levels of 2iP were used, at which point only axillary buds present on the explants were released. Proliferated shoots could be rooted ex vitro without auxin treatment. Optimal rooting occurred under high-light conditions. Plants were transplanted to the field for comparison to conventionally propagated material. Chemical names used: gibberellic acid (GA3), N-(3-methyl-2-butenyl)-1H-purin-6-amine (2iP), 1H-indole-3-butanoic acid (IBA).

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Inmaculada Vila, Ester Sales, Javier Ollero, Jesús Muñoz-Bertomeu, Juan Segura, and Isabel Arrillaga

shoot-tips (1 to 2 mm in length) from both seedlings (15-d-old) and previously established shoot cultures of seedlings and adult plants (6-week-old) were individually transferred to test tubes containing 20 mL of proliferation media. Four proliferation

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Tracy S. Hawkins, Nathan M. Schiff, Emile S. Gardiner, Theodor Leininger, Margaret S. Devall, Dan Wilson, Paul Hamel, Deborah D. McCown, and Kristina Connor

zeatin yielded a minimum twofold proliferation rate. Zeatin did cause slight basal callusing, which was either pinched off at rooting or ignored, depending on size. Stabilization of L . melissifolia shoot cultures was complete after ≈10 rounds of

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Kaitlin J. Palla, Rochelle R. Beasley, and Paula M. Pijut

-hardy Russian hybrid, and nearly seedless. Scion wood from each genotype was grafted onto seedling rootstock of field-grown common persimmon. In vitro shoot culture establishment. All actively growing stems from 2-year-old grafted stock plants growing in the

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Jin Cui, Juanxu Liu, Min Deng, Jianjun Chen, and Richard J. Henny

ex Fr.) has become the most common disease of arrowhead vine. This opportunistic airborne fungal pathogen particularly occurs during the ex vitro rooting of microcuttings after shoot culture because the cutting base is especially susceptible to this

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Carrie A. Radcliffe, James M. Affolter, and Hazel Y. Wetzstein

the reintroduction and augmentation of natural populations. The objective of this study was to determine the efficacy of using an in vitro protocol to regenerate proliferating shoot cultures from 34 georgia plume genotypes obtained from divergent wild

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Sullivan Lynch, Rachel K. Johnston, Ron O. Determann, Jennifer M. Cruse-Sanders, and Gerald S. Pullman

on the left is empty; the one on the right is filled. ( B ) Seedling growing on growth regulator-free half-strength Murashige and Skoog (MS) medium. ( C ) Shoot culture forming a miniature hedge growing on multiplication medium containing half

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Eric W. Mercure, Carol A. Auer, and Mark H. Brand

Tissue proliferation (TP) is characterized primarily by the formation of galls or tumors at the crown of container-grown rhododendrons propagated in vitro. However, TP of Rhododendron `Montego' is observed initially in in vitro shoot cultures and it is characterized by the formation of multiple shoots with small leaves and nodal tumors. The formation of shoots in `Montego' TP (TP+) shoot cultures occurs without the presence of exogenous cytokinin in the medium, unlike normal `Montego' (TP–) shoot cultures, which require cytokinin for shoot growth. Structural studies have shown that tumors are composed of many adventitious buds and parenchyma cells, suggesting that TP is a result of abnormal cytokinin regulation that is controlling tumor and shoot formation. Two approaches are being used to determine if differences in cytokinin concentration and/or metabolism exist between TP+ and TP– shoot cultures. In the first approach, shoot cultures are grown in vitro for 1 week in the presence of tritiated isopentenyladenine (iP). Cytokinin uptake and metabolism are analyzed using HPLC and other analytical methods. Experiments suggest that extensive degradation and N-glucoside conjugation occur in TP+ and TP– shoots, resulting in the removal of most of the exogenous iP. In the second approach, the levels of endogenous cytokinins such as iP, isopentenyladenosine, zeatin, and zeatin riboside, are being measured in TP+ tumors and shoots and in TP– shoots by an ELISA method.