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ARS Home » Northeast Area » Washington, D.C. » National Arboretum » Floral and Nursery Plants Research » Research » Publications at this Location » Publication #409294

Research Project: Manage, Expand, and Evaluate the U.S. National Collection of Temperate-adapted Woody Landscape Plant Germplasm and Associated Descriptive Data

Location: Floral and Nursery Plants Research

Title: Genome size, ploidy estimates, and leaf morphology of temperate Lindera (Lauraceae) cultivated in North America

item JOHNSON, EMILY - Orise Fellow
item Pooler, Margaret
item Rounsaville, Todd

Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/16/2024
Publication Date: 4/8/2024
Citation: Johnson, E., Pooler, M.R., Rounsaville, T.J. 2024. Genome size, ploidy estimates, and leaf morphology of temperate Lindera (Lauraceae) cultivated in North America. Genetic Resources and Crop Evolution.

Interpretive Summary: Lindera is a genus of shrubs or small trees occurring in temperate to tropical regions of Asia and North America and are commonly known as ‘spicebush’ for their distinct aromatic smell and sharp taste of the leaves, fruit, bark, and roots. Worldwide, species in this genus have considerable diversity in form, cold-hardiness, growth rate, and foliage traits, but are not often used as ornamental plants. In the U.S., interest in this genus is growing for its horticultural and conservation relevance. To explore the genetic relationships of plants in this genus for their horticultural, conservation, and breeding potential, ARS scientists from the U.S. National Arboretum measured the DNA content and leaf morphology traits of 100 accessions of Lindera, representing 25 species. They found considerable variability among species in DNA content, ploidy level, and leaf morphological traits, indicating evolutionary differences within the genus. Data from this study provides a strong base for evolutionary evaluation, breeding and development of new hybrids, and insights into future research on the interaction of genome size and environmental factors.

Technical Abstract: The genus Lindera (Lauraceae) consists of ca. 100 species of shrubs and trees with economic value for medicinal drugs as well as oils used in aromatics, soaps, and biodiesel. Only a few Lindera species have received attention as ornamental plants, but considerable interspecific diversity in habit, foliage, and fruit offer significant potential to plant breeders and horticulture. We used flow cytometry to determine genome sizes of 100 accessions representing 25 temperate Lindera taxa and estimated ploidy level for each accession. In addition, we assessed stomatal size, density, and specific leaf area among samples. We found a nearly twelve-fold difference in 2C DNA context among accessions. We confirmed previous reports of diploid and tetraploid Lindera taxa, and present evidence of triploid (L. fruticosa and L. glauca), hexaploid (L. angustifolia and L. umbellata), and octoploid (L. angustifolia, L. glauca var. salicifolia, and L. salicifolia) taxa for the first time. Although most taxa sampled were diploid, our findings indicate multiple cytotypes exist for L. angustifolia (6x and 8x) and L. umbellata (2x and 6x). Ploidy level had a significant positive relationship with stomatal size, but not stomatal density nor specific leaf area. Overall, these findings provide insight for plant evolutionary biologists, taxonomists, and breeders interested in Lindera, which remains to be resolved phylogenetically and has not been utilized in ornamental breeding programs. In addition, these data are relevant to plant ecologists and conservationists, particularly in North America where the Laurel wilt pathogen is threatening Lauraceae taxa, including the endangered species Lindera melissifolia and L. subcoriacea.