Mark H. Brand

Agar and ammonium nitrate influence hyperhydricity, tissue nitrate and total nitrogen content of serviceberry (Amelanchier arborea) shoots in vitro

Shoot tip cultures of Amelanchier arborea Michx.f. were grown on Murashige & Skoog or Woody Plant (WP) medium containing 4.4 μM benzyladenine and various concentrations of agar. Increases in agar concentration affected various culture growth variables, decreased culture hyperhydricity and increased tissue nitrate concentration. Additions of ammonium nitrate to cultures grown on WP medium containing 0.4% agar increased all growth variables measured except percent dry weight. Hyperhydricity and tissue nitrate concentration also increase in response to increasing ammonium nitrate in the medium. Since hyperhydricity was shown to be both positively and negatively correlated with increases in tissue nitrate content, it is unlikely that tissue nitrate level alone directly affects hyperhydricity.

Detecting the influence of ornamental Berberis thunbergii var. atropurpurea in invasive populations of Berberis thunbergii (Berberidaceae) using AFLP1.

Japanese barberry (Berberis thunbergii DC.) is a widespread invasive plant that remains an important landscape shrub represented by ornamental, purple-leaved forms of the botanical variety atropurpurea. These forms differ greatly in appearance from feral plants, bringing into question whether they contribute to invasive populations or whether the invasions represent self-sustaining populations derived from the initial introduction of the species in the late 19th century. In this study we used amplified fragment length polymorphism (AFLP) markers to determine whether genetic contributions from B. t. var. atropurpurea are found within naturalized Japanese barberry populations in southern New England. Bayesian clustering of AFLP genotypes and principal coordinate analysis distinguished B. t. var. atropurpurea genotypes from 85 plants representing five invasive populations. While a single feral plant resembled B. t. var. atropurpurea phenotypically and fell within the same genetic cluster, all other naturalized plants sampled were genetically distinct from the purple-leaved genotypes. Seven plants from two different sites possessed morphology consistent with Berberis vulgaris (common barberry) or B. ×ottawensis (B. thunbergii × B. vulgaris). Genetic analysis placed these plants in two clusters separate from B. thunbergii. Although the Bayesian analysis indicated some introgression of B. t. var. atropurpurea and B. vulgaris, these genotypes have had limited influence on extant feral populations of B. thunbergii.

Fecundity of Japanese Barberry (Berberis thunbergii) Cultivars and Their Ability to Invade a Deciduous Woodland

Abstract Japanese barberry is an important landscape shrub that has a demonstrated potential to be invasive in ∼30 states across the central and northern United States. Forty-six cultivars were evaluated for their potential to produce fruits and seeds in a randomized, replicated field planting. Seeds from a subset of cultivars were evaluated for their ability to germinate and survive as seedlings in a deciduous woodland. Seed production for cultivars varied from no seeds to more than 12,000 seeds plant−1 and the number of seeds per fruit ranged from 0.1 to 1.8. Five cultivars produced fewer than 100 seeds plant−1, and two cultivars failed to produce fruit. When plants were allowed to mature for 4 to 5 yr beyond the first evaluation time, cultivars exhibited significant increases in fruits per plant, producing as much as 35,000 fruits plant−1 (‘Sparkle’). ‘Golden Devine’ and ‘Red Chief’, fruitless cultivars at the first evaluation, produced 165 and 20 fruit plant−1, respectively, at the follow-up evaluation, demonstrating that long-term evaluation of cultivars is necessary to accurately assess sterility. Between 12.5 and 31% cultivar seed sown in a deciduous woodland germinated, and seedlings survived at rates between 5.6 and 29.3%. Coupling cultivar seed-production data with germination and survival data in a deciduous woodland suggests that even cultivars producing as few as 100 seeds annually have the potential to contribute a few seedlings each year to a natural area. Nomenclature: Japanese barberry, Berberis thunbergii DC Management Implications: Japanese barberry cultivars represent a substantial economic value to the nursery and landscape industries because they are popular, durable plants, widely used for landscaping. Unfortunately, Japanese barberry is also an invasive plant, and some states have imposed laws preventing the propagation and sale of the species and all cultivars. Cultivars of Japanese barberry look and behave differently from the species, with many being dwarf forms with purple or yellow foliage. The dramatic visual differences between cultivars of Japanese barberry and the species have led some to suggest that certain cultivars may be noninvasive or have a lower potential for rapid establishment in natural communities and could be exempted from species bans. The objective of this study was to evaluate the fecundity of a wide range of commercially available Japanese barberry cultivars to determine whether any could be considered noninvasive. We determined fruit production, seed production, and germination rates for 46 cultivars of Japanese barberry and its hybrids. Using seed from a representative subset of cultivars, we also determined the potential each cultivar had to germinate, survive, and grow in a deciduous woodland. Cultivars varied considerably in their seed production from more than 12,000 seeds to no seeds, and several cultivars produced fewer than 100 seeds plant−1. When plants were allowed to mature for 4 to 5 yr beyond the first evaluation time, cultivars exhibited significant increases in fruits per plant. ‘Sparkle’ produced more than 35,000 fruits plant−1 and ‘Golden Devine’ and ‘Red Chief’, which initially appeared to be fruitless, produced 165 and 20 fruit plant−1, respectively. To accurately assess reproductive potential of cultivars, it is necessary to conduct evaluations for durations that are longer than those typically reported and to provide ample opportunities for cross-pollination. Cultivar seed germination rates were between 12.5 and 31% in a deciduous woodland, and seedlings survived at rates between 5.6 and 29.3%. By combining seed production data with establishment data in a deciduous woodland, even cultivars producing as few as 100 seeds yr−1 in the landscape have the potential to contribute a few seedlings each year to a natural area. Most barberry cultivars clearly cannot be considered noninvasive, and even those that are the least fecund, can still be minimally invasive if they reach an age of 10 yr or more.

Ornamental Plant Transformation

Abstract Ornamental plant transformation has advanced considerably in the last decade. Now over 40 genera have been reported to be transformed. The primary methods of creating transgenic ornamental species have been Agrobacterium tumefaciens-medmtedtransformation and microprojectile bombardment. The vast majority of reports indicate the use of Agrobacteriummedmtedtransformation employing binary vectors and virhelper plasmids or supervirulence genes. Many reports are of transformation with the uidA reporter gene driven by the 35S cauliflower mosaic virus promoter, but recent efforts are now focusing on trait genes including disease resistance, flower color, flower longevity, floral scent and plant habit. Greater use of tissue specific and inducible promoters promises to enhance the functionality and usefulness of introduced trait genes. While technical challenges for production of transgenic ornamental plants still exist, the greatest challenges to realizing the potential benefits of transgenic ornamental plants are questionable public acceptance of transgenic plants and the prohibitive costs of generating environmental impact data needed to gain regulatory clearance.

Occurrence and Fertility of Feral Hybrid Barberry Berberis × ottawensis (Berberidaceae) in Connecticut and Massachusetts

Abstract Berberis ×ottawensis is the hybrid of B. vulgaris (common barberry) and B. thunbergii (Japanese barberry). In the wild, this interspecific taxon appears to have been largely overlooked. Here, we report that this hybrid is relatively widespread in Connecticut and Massachusetts. Furthermore, we present evidence that the hybrid individuals are capable of producing some viable seed and pollen.

Initiating cultures ofHalesia andMalus: influence of flushing stage and benzyladenine

Shoot tips ofHalesia carolina L. andMalus domestica Borkh. ‘Golden Delicious’ collected at various times during the spring growth flush varied considerably in their ability to initiate shoot proliferating cultures. Shoot tips collected during, or at the end of, the period of most rapid shoot elongation exhibited weak shoot proliferation potential, while shoot tips collected before or after this period were capable of strong shoot proliferationin vitro. Benzyladenine concentrations in the culture media above 22.5 µM (Halesia) or 44.5 µM (Malus) were inhibitory during the period between bud break and rapid shoot elongation. Benzyladenine concentrations of 22.5 or 44.5 µM were useful in enhancing shoot proliferation potential in shoot tips collected after the period of rapid shoot elongation, but before the onset of summer dormancy. Benzyladenine concentration did not affect the shoot proliferation potential of shoot tips collected during the rapid shoot elongation phase of the spring growth flush.Halesia andMalus shoot tips behaved similarly in this study. For deciduous woody perennials, the time of explant collection for culture initiation could be refined on the basis of these results.

Development and characterization of microsatellite markers for Berberis thunbergii (Berberidaceae).

PREMISE OF THE STUDY Microsatellite markers were isolated and characterized in Berberis thunbergii, an invasive and ornamental shrub in the eastern United States, to assess genetic diversity among populations and potentially identify horticultural cultivars. METHODS AND RESULTS A total of 12 loci were identified for the species. Eight of the loci were polymorphic and were screened in 24 individuals from two native (Tochigi and Ibaraki prefectures, Japan) and one invasive (Connecticut, USA) population and 21 horticultural cultivars. The number of alleles per locus ranged from three to seven, and observed heterozygosity ranged from 0.048 to 0.636. CONCLUSIONS These new markers will provide tools for examining genetic relatedness of B. thunbergii plants in the native and invasive range, including phylogeographic studies and assessment of rapid evolution in the invasive range. These markers may also provide tools for examining hybridization with other related species in the invasive range.

Tissue proliferation condition in micropropagated ericaceous plants

Tissue proliferation (TP) is an abnormal tumor-like growth produced at or near the crown of the plant, but may also be found on aerial plant parts of some genotypes. Basal tumors may or may not be accompanied by proliferation of compact shoots with short internodes and a whorled leaf arrangement. Genera exhibiting TP include Rhododendron, Kalmia and Pieris of the Ericaceae family. Development of TP symptoms in a plant is highly correlated to a history of micropropagation and also to genetic background of the genotype. Similarities of TP symptoms to crown gall caused by Agrobacteriumtumefaciens led many to initially believe TP to be a form of crown gall, but all evidence suggests that a pathogen is not involved in the TP disorder. Abnormal lignotuber formation is another possible cause for TP for which little supportive evidence could be developed. An epigenetic condition, possibly cytokinin habituation, is the possible cause of TP that is best supported by the majority of research evidence. It is likely that TP is induced in vitro by adventitious shoot formation, resulting from high cytokinin concentrations used to rapidly proliferate shoots. Some nursery production practices may result in increased TP symptoms development post-propagation. TP is well managed now due to greater awareness and adoption of sound micropropagation practices for ericaceous plants by tissue culture labs.

Vouchering Photinia villosa (Rosaceae) as a wild plant in Connecticut

Photinia villosa (Thunb.) DC., Oriental photinia, is a shrub in the subtribe Pyrinae (formerly Maloideae) of the Rosaceae (Campbell et al. 2007). This species is native to Japan, Korea, and China and was introduced into worldwide cultivation around 1865 (Dirr 2009). Photinia villosa is a rather inconspicuous shrub resembling an Aronia Medikus species. The most obvious feature clearly differentiating P. villosa is its warty pedicels (Dirr 2009). This species is known to be established as a wild plant in Delaware, Pennsylvania, New Jersey, and New York (Glenn 2013; USDA, NRCS 2015). In New Jersey, Photinia villosa is considered to be an invasive plant species (Central Jersey Invasive Species Strike Team 2015). Photinia villosa is also reported by Glenn (2013) as occurring in Fairfield County, Connecticut, though it is unclear if a voucher was collected. This species is not reported as occurring in Connecticut (Dreyer 2013), or any other New England state (Haines 2011). The Glenn (2013) report is highly credible, though many floras require a voucher specimen for acceptance of a species occurring in an area. Here we report that a population of P. villosa was found growing in Windsor, CT, outside of cultivation, and that voucher specimens for this population have been collected. The population was scattered throughout a disturbed woodland, with individuals seen in the vicinity of GPS coordinates 4184856.8692 N, 7284058.0512 W. Approximately 10 P. villosa shrubs were observed growing on the bank of a small stream with other invasive species and native wetland shrubs. It is

Kousa Dogwood Benthamidia japonica (Cornaceae) established as a free-living species in Massachusetts

Kousa dogwood, Benthamidia japonica (Sieb. & Zucc.) Hara syn. Cornus kousa Bürger ex Hance, is a small tree native to Japan, China, and Korea that was introduced into cultivation worldwide in 1875 (Dirr 2009). This species is used extensively as an ornamental throughout eastern North America and can be grown in hardiness zones 5 to 8 (Dirr 2009). Benthamidia japonica is similar to the native North American species Benthamidia florida (L.) Spach. though it differs in several characteristics. The most obvious character when the specimens were collected were the acuminate leaf apices of B. japonica, in contrast to those of B. florida which are blunt (Dirr 2009). Additionally, it could be observed that the winter buds were elongated and dark brown to black as is expected of B. japonica and not the turbinate and gray buds of B. florida (Dirr 2009). Haines (2011) also uses fruit, leaf venation and petiole characteristics to distinguish the two species. On October 27, 2015 while conducting a Framingham State University class field trip, approximately 20 individuals of Benthamidia japonica were observed throughout the Macomber property, at the approximate GPS coordinates of 428175.64 N, 7182711.5194 W, in Framingham, Massachusetts, mostly near the trail toward Singletary Lane. The individuals ranged from about 10 cm to 150 cm in height. No large planted specimens of B. japonica were observed in the vicinity. The species was established as an understory plant in a disturbed mixed woodland, with Pinus L., Betula L., Quercus L., and Carya Nutt. overhead, and did not appear to be planted. Though well established,