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Robert M. Jetton, John Frampton and Fred P. Hain

This study tested the effects of cutting length and auxin (NAA) concentration on adventitious root formation in softwood stem cuttings from mature eastern hemlock, Tsuga canadensis (L.) Carr., and carolina hemlock, T. caroliniana Engelm. Overall rooting percentage (41%) and percent mortality (22%) were higher for eastern hemlock compared with carolina hemlock (10% rooting and 13% mortality). Rooting percentage of each species responded differently to varying auxin concentrations (0, 1, 2, 4, 8 mm NAA). Maximum rooting (56%) for eastern hemlock occurred at 0 mm NAA; then decreased with increasing auxin concentration. Carolina hemlock rooting percentage increased from the control to a maximum (16%) at 1 mm NAA; then decreased with increasing auxin concentration. For both species, the lowest mortality occurred at the same auxin concentration as maximum rooting. The highest rates of mortality coincided with the same concentrations as the lowest rooting percentages. At all auxin concentrations, eastern hemlock had a higher number of roots and greater total root length relative to carolina hemlock. Mortality among 6-cm stem cuttings was twice that observed for 3-cm cuttings of both species. However, 6-cm cuttings of eastern hemlock that did form adventitious roots had more roots and longer total root length compared with 3-cm cuttings. Chemical name used: 1-naphthalenacetic acid.

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Darren J. Hayes and Bryan J. Peterson

We assessed adventitious root formation on stem cuttings of mountain fly honeysuckle [Lonicera villosa (Michx.) Schult.] in separate experiments using overhead mist and subirrigation systems. The concentration of applied potassium salt of indole-3-butyric acid (K-IBA) and the proportions of coarse perlite and milled peatmoss in the propagation medium were varied within both systems. Across treatments, 98% of cuttings in the overhead mist system and 85% of cuttings in the subirrigation system produced roots. In the overhead mist system, root volume, root dry weight, and number of root tips were greatest among cuttings treated with 4000 to 12,000 mg·L−1 K-IBA and stuck into 100% perlite. In the subirrigation system, root dry weight was not significantly affected by K-IBA concentration, but the greatest root volume and number of root tips were produced by cuttings treated with 8000 or 12,000 mg·L−1 K-IBA and stuck into 100% perlite. Despite the natural affinity of mountain fly honeysuckle for moist, organic soils, all of the 18 rooted cuttings we planted in a landscape trial survived and grew appreciably with minimal care over 2 years in a mineral field soil. We conclude that cuttings of mountain fly honeysuckle can be propagated readily by overhead mist or subirrigation, that root system quality is improved substantially by increasing K-IBA concentration and using coarse perlite without peatmoss, and that mountain fly honeysuckle can be grown in typical horticultural landscapes.

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Mariateresa Cardarelli, Youssef Rouphael, Francesco Saccardo and Giuseppe Colla

Research was conducted at the University of Tuscia (central Italy) to validate the propagation system for globe artichoke (Cynara cardunculus var. scolymus) described in a previous paper for a 1-year production cycle. The resulting globe artichoke plants were used in a 2-year field trial to investigate the field response of plantlets obtained with our propagation technique in comparison with plantlets produced by in vitro propagation and by offshoots harvested in commercial fields. The total number of artichoke plantlets obtained with our propagation system was 62.7 plantlets/m2 per year. In the first year, the globe artichoke production (bud number and fresh bud weight) was higher in plants obtained with our propagation system and by micropropagation than in those obtained from offshoots harvested in commercial fields. The production cost of plantlets obtained with our propagation technique was 52% lower than those of the micropropagated plantlets. This could lead to a significant reduction of production costs for artichoke growers, while preserving the advantages of in vitro propagation (disease-free plants and plant uniformity).

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Ji-Yu Zhang, Zhong-Ren Guo, Rui Zhang, Yong-Rong Li, Lin Cao, You-Wang Liang and Li-Bin Huang

temperatures provides a new method that improves vegetative propagation, and pecan has the value of using the waste material from budding to increase plant numbers by using the cuttings that are normally discarded. This report offers a feasible and less

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Michael T. Martin Jr., Geoffrey M. Weaver, Matthew R. Chappell and Jerry Davis

). Several studies have examined tissue nutrient concentrations of leafy stem cuttings (henceforth referred to as “cuttings”) during vegetative propagation in nutrient-free media. Good and Tukey (1967) showed that P was mobilized from older leaves to lower

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Richard Meilan, Caiping Ma and Steven H. Strauss

We assessed the stability of transgene expression in 79 transgenic lines (i.e., transformation events) of hybrid poplars during several years of field trials. The transgenic lines were comprised of 40 lines of hybrid cottonwoods (P. trichocarpa × P. deltoides) that were grown at three field sites, and 39 lines of hybrid aspens (section Leuce, P. alba × P. tremula) that were grown at a single field site. All the lines were transformed with a binary construct that included two genes that confer tolerance to glyphosate (GOX and CP4), a gene encoding resistance to the antibiotic kanamycin (nptII), and a visible marker gene (GUS). Agrobacterium tumefaciens was used for transformation; callogenesis and organogenesis occurred under kanamycin selection. In addition to repeated applications of herbicide to test stability of transgene expression, for the first time, we challenged ramets of 40 lines that had not previously been tested for herbicide resistance in their fourth season of vegetative growth. We report on the stability of herbicide resistance and GUS expression and evidence for somaclonal variation in growth and leaf morphology.

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Karen L. Panter, Rebecca E. Ashley, Karin M. Guernsey and Caroline M. Johnson

Osha (Ligusticum porteri) is a perennial plant native to the Rocky Mountain region of the United States and has been used as a medicinal herb to alleviate certain ailments caused by viruses, yeasts, and other microbes. It is generally harvested in the wild and is believed to be in danger of overharvest. The objectives of this study were to determine if osha could be grown successfully from seeds, seeds still attached to umbels, root cuttings, and/or vegetative crown cuttings. Seeds were harvested from the wild in Fall 2000. Roots were collected in May 2001. Seeds, either detached or attached to umbels, were given one of four treatments: 1) no stratification; 2) 6 weeks at 4.4 °C (40 °F); 3) 4 weeks each alternating 4.4 °C, then 12 hour 20.0 °C (68 °F) and 12 hours 30.0 °C (86 °F); or 4) 12 weeks at 4.4 °C. Roots were divided into crown cuttings, each containing a vegetative node, and were placed on a 21.1 °C (70 °F) mist propagation bench until rooted. Twelve weeks of stratification, whether seed was detached or attached to umbels, were beneficial for germination of osha seeds, but only gave about 11% emergence. Propagation from root cuttings was not successful. Propagation via vegetative crown cuttings was most successful, with 90% of cuttings rooting. Vegetative propagation of osha appears to be the most promising method, preferable over seed propagation.

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Sandra B. Wilson, Robert L. Geneve and Fred T. Davies

Interactive web-based questions were developed for students to review subject matter learned in an online plant propagation course. Articulate Storyline software was used to build nearly 250 review questions with five different testing styles to ascertain proficiency in subject areas, including the biology of propagation, the propagation environment, seed propagation, vegetative propagation, micropropagation, and cell culture. Questions were arranged to correspond to the supporting textbook chapters in Hartmann and Kester’s Plant propagation: Principles and practices, ninth edition. These are open access and available to instructors and students worldwide. Users received immediate feedback for each question answered correctly or incorrectly. The system remembers where one leaves off, which enables starting and stopping multiple times within a chapter. Means of pre- and posttest responses to nine content knowledge items showed that students perceived a significant content knowledge gain in the course. These online interactive reviews can be adapted easily to other courses in a variety of fields, including horticulture, botany, systematics, and biology. They can also be expanded to overlay multiple objects and trigger events based on user response. Since inception, the website hosting these online reviews averaged 156 unique visitors per month. Students have reported this to be a useful tool to prepare them for course exams.

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Nan Tang, Xiuting Ju, Yafan Hu, Rulong Jia and Daocheng Tang

, 1976 ). Seed propagation of lilies is time-consuming because of the long juvenile stage of these plants. Generally, at least 3 years are required to obtain commercial bulbs from seeds. Therefore, vegetative propagation is preferred for the large