Arbuscular mycorrhizal colonization (total and arbuscules) were measured in roots of 10 species of eastern North American woody plants. Five were non-native invasive and 5 were native species. Roots were collected from ingrowth cores over three harvests during a single season, from a common garden. Diameter was estimated from published root density and specific root length values for each species.

Arbuscular mycorrhizal colonization (total and arbuscules) were measured in roots of 10 species of eastern North American woody plants. Five were non-native invasive and 5 were native species. Roots were collected from ingrowth cores over three harvests during a single season, from a common garden. Diameter was estimated from existing data on root density and specific root length. The aim of the study was to investigate the relationship between species nativity and mycorrhizal colonization, and to correlate mycorrhizal colonization with plant traits.

We measured AMF colonization in archived roots that were originally collected by Jo et al. (2017) for root productivity and chemistry measurements. Root samples were obtained from harvests of point-in-space ingrowth cores (Milchunas et al., 2005) installed in September 2013 and harvested in late May, late July, late September and late November of 2014. Ingrowth cores made of 1x1 cm plastic mesh (4 cm diameter) were installed at a depth of 0-10 cm and filled with root-free soil from the site. Each plot contained 9-12 cores from which fine roots (including first to third order) were pooled to obtain one representative sample per plot at each harvest date. Collected roots were cleaned using deionized water and dried at 65 °C for >2 days. We used roots from the May, July and September 2014 harvest dates for AMF scoring, which spanned the majority of the growing season. Dried fine roots were rehydrated in water, and cleared and stained using the ink and vinegar method (Vierheilig and Piché, 1998). Total AMF colonization was quantified using the magnified line intersect method (McGonigle et al., 1990) at 400x magnification. Colonization by arbuscules, the primary sites of resource exchange for the symbiosis, were also scored. In some cases, root material from a sample was consumed in previous measurements of root chemistry conducted by Jo et al. (2017) or roots were too difficult to sufficiently clear for visual inspection, reducing the sample size for some species. Each species was represented by 3 to 9 replicates (median = 8.5) in the final dataset, for a total sample size of 69 observations. Specific root length (SRL, m g-1) and root tissue density (RTD, g cm-3) from Jo et al. (2015) were used to calculate average root diameter for the same species (mm). The following plant species were included: Celastrus orbiculatus Thunb., Celastrus scandens L., Frangula alnus Mill., Frangula caroliniana (Walter) A. Gray, Lonicera canadensis W. Bartram ex Marshall, Lonicera sempervirens L., Lonicera villosa (Michx.) Schult., Lonicera fragrantissima Lindl. & Paxton, Lonicera japonica Thunb., Lonicera morrowii A. Gray.

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Jo, I., J. D. Fridley, and D. A. Frank. 2015. Linking above- and belowground resource use strategies for native and invasive species of temperate deciduous forests. Biological Invasions 17: 1545-1554.

McGonigle, T. P., M. H. Miller, D. G. Evans, G .L. Fairchild, and J. A. Swan. 1990. A new method which gives an objective measure of colonization of roots by vesicular-arbuscular mycorrhizal fungi. New Phytologist 115: 495-501.

Milchunas, D. G., A. R. Mosier, J. A. Morgan, D. R. LeCain, J. Y. King, and J. A. Nelson. 2005. Root production and tissue quality in a shortgrass steppe exposed to elevated CO2: using a new ingrowth method. Plant and Soil 268: 111–122.

Vierheilig, H, and Y. Piché. 1998. A modified procedure for staining arbuscular mycorrhizal fungi in roots. Journal of Plant Nutrition and Soil Science 161: 601–602.