Juniperus Virginiana Research Articles

Larvicidal activity in vitro of essential oils against Cochliomyia hominivorax

Cochliomyia hominivorax, from the family Calliphoridae, is responsible for causing most myiases in domesticated animals in Brazil. As alternatives to conventional treatments, essential oils (EOs) could possibly be used as natural control of ectoparasites. The aim of this study was to evaluate the in vitro activity of EOs from Salvia sclarea L., Rosmarinus officinalis L., Lavandula hybrida Reverchon, Citrus bergamia Risso, Citrus paradisi L., Juniperus virginiana L., Copaifera reticulata Ducke, Illicium verum Hook f., Pelargonium roseum, Cymbopogon winterianus Jowitt, Cymbopogon flexuosus Steud, Eugenia caryophyllus Spreng, Cinnamomum cassia Presl, Thymus vulgaris L. and Origanum vulgare L. against third-instar larvae of C. hominivorax. To evaluate the mortality rate, filter paper tests were performed at different concentrations and verified after 24 h and 48 h. Essential oils of T. vulgaris, O. vulgare and I. verum induced 100% mortality in the screening test, and their main active components (thymol, carvacrol and anethol, respectively) were also tested alone. In this new test, lethal concentrations (LC50) after 24 h and 48 h, respectively, were 407.1 and 314.2 µg.cm-² for T. vulgaris, 540.9 and 253.8 µg.cm-² for O. vulgare, 314.2 µg.cm-² (after 48 h) for I. verum, 255.6 and 102.3 µg.cm-² for thymol, 970.5 and 931.1 µg.cm−2 for carvacrol and 559.4 µg.cm−2 (after 48 h) for anethol. These results showed the potential of these EOs and their main components for development of ectoparasiticides for veterinary use, especially T. vulgaris EO and thymol.

Temporal changes in genetic diversity reveal small-scale invasion dynamics of the eastern redcedar (Juniperus virginiana var. virginiana) in the Lakeside Daisy State Nature Preserve in Ohio

AbstractEastern redcedar (Juniperus virginiana L. var. virginiana; hereafter ERC) is a native species currently invading open areas and grasslands outside of its original range in the United States. We studied ERC’s invasion patterns in the Lakeside Daisy State Nature Preserve (LDSNP), a short grass prairie located on the Marblehead Peninsula in Ohio, examining the changes in the genetic diversity and structure of the encroaching population. We investigated the relative importance of long-distance dispersal versus diffusion in the invasion of this short grass prairie by ERC. We use eight microsatellite marker loci to infer gene flow from external sources versus within-population recruitment. We found that the older trees in this preserve were less than 50 yr old, indicating that the population was established between 1970 and 1980. When we grouped trees into five age categories of 10-yr increments, we found that the allelic diversity, as indicated by the average number of alleles per locus, increased as the age of the trees decreased. We also found that not all loci were in Hardy-Weinberg equilibrium, probably due to the arrival of new variants in the preserve. Moreover, heterozygosity remained high, with an excess of heterozygotes in all age groups (F = −0.163 ± 0.046). Principal coordinate analysis showed two distinct groups of trees in the LDSNP. Analysis of the cryptic population structure of the ERC trees using STRUCTURE revealed four ancestral clusters in the ERC population. All ancestral clusters are present in all age groups, suggesting that all trees sampled are derived from an admixed population. Furthermore, the high observed heterozygosity and lack of inbreeding in this dioecious species maintained all ancestral clusters over time. Overall, our findings indicate that ERC encroachment of the LDSNP results from multiple and reiterated gene flow events from the edge of the range through animal-mediated seed dispersal.

How could the bioactivity of emulsifiable concentrate and nano-emulsion formulations of Rheum palmatum and Juniperus virginiana essential oils affect Tetranychus urticae (Acari: Tetranychidae) and its bio-agent, Phytoseiulus persimilis (Acari: Phytoseiidae)

Two types of formulations, emulsifiable concentrates (ECs) and nano-emulsions (NEs), were conducted to enhance the activity of the Rheum palmatum L. and Juniperus virginiana L. essential oils (EOs). The efficacy of EOs, ECs, and NEs was evaluated under laboratory and semi-field conditions against Tetranychus urticae Koch eggs and females. In addition, assessing their selectivity towards the predatory mite, Phytoseiulus persimilis Athias-Henriot. The tested ECs and NEs showed toxicity against T. urticae females higher than bulk oils, and all caused 100% un-hatchability of T. urticae eggs. With the exception of EOs and R. palmatum EC, neither the prepared ECs nor NEs showed any phytotoxicity symptoms on treated plants. The residual effects of tested materials were dissipated over time. Juniperus virginiana EO, EC and NE were compatible with P. persimilis. Tested ECs and NEs can aid in more sustainable crop management, to develop low-risk solutions to replace the use of pesticides.

Effective stakeholder engagement in environmental problem-solving though group model building: An Oklahoma case study

Stakeholder engagement is a vital, yet under-accessed and under-studied, resource for tackling wicked environmental problems. This paper examines mental models – cognitive representations of “real” systems – refined through group model building (GMB) with stakeholders concerned with environmental issues in the US state of Oklahoma. During GMB, a diverse group of high-level decision makers met with a variety of physical and social scientists to collaborate on mental models concerning three environmental focus areas in Oklahoma: encroachment of eastern red cedar, grid and infrastructure resilience, and marginal water use and re-use. We ask: how do individuals from diverse stakeholder groups describe causes and consequences of key environmental problems in Oklahoma? Results from this analysis advance efforts toward developing socially sustainable solutions for environmental problems in Oklahoma and beyond.

Some Like It Dry: Differences in Water Use Strategies between Historic and Range-Expanding Populations of Juniperus virginiana

Next article No AccessSome like it dry: Differences in water use strategies between historic and range expanding populations of Juniperus virginianaRandall Long, David Ward, Chiara Baker, and Juliana S MedeirosRandall Long Search for more articles by this author , David Ward Search for more articles by this author , Chiara Baker Search for more articles by this author , and Juliana S Medeiros Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by International Journal of Plant Sciences Just Accepted Article DOIhttps://doi.org/10.1086/725385 HistoryAccepted March 31, 2023 © 2023 The University of Chicago. All Rights reserved.PDF download Crossref reports no articles citing this article.

Integrating fine root diameter and watershed mapping to characterize rhizosphere hydrology

Root morphology and soil hydraulic characteristics were integrated using watershed distance mapping to show water distribution and uptake across the plant-soil interface. Poplar (Populus deltoides, P. trichocarpa), maize (Zea mays), juniper (Juniperus virginiana), grape (Vitis rotundifolia) and maple (Acer saccharum) seedlings were grown in sand, after which root diameter and soil water dynamics were assessed via sequential neutron radiography. Three local soil regions (root-soil interface or edge, rhizosphere, bulk soil) were classified based on both radial distance from the root surface and diameter of the nearest root, from which changes in water content and distribution were characterized using digital image processing. Water content dynamics across the rhizosphere showed two different species-independent processes: a consistently elevated water content at the root-soil edge interface which increased with root diameter, and hysteresis as the rhizosphere transitioned to bulk soil (∼0.5 cm from the root), independent of root diameter. Water uptake per unit root surface area declined exponentially with root diameter, independent of species. Results highlight the species-independent hydrologic characteristics of the rhizosphere and the potential for evaluating them in a local spatially connected soil context. Avenues for improved integration of soil and root characteristics are discussed.

Conversion of native grassland to coniferous forests decreased stocks of soil organic carbon and microbial biomass

AimsEncroachment of woody species into grasslands is a global phenomenon that affects ecosystem services, including soil organic carbon (SOC) storage and microbial community structure. We determined stocks of SOC and soil microbial biomass as affected by conversion of grasslands to coniferous forests.MethodsWe examined SOC and soil δ13C signatures under three vegetation covers: native grasslands, eastern redcedar (Juniperus virginiana), and ponderosa pine (Pinus ponderosa), at six soil depths (0 − 10, 10 − 30, 30 − 100, 100 − 170, 170 − 240, 240 − 300 cm). Fatty acid methyl esters (FAMEs) were used to quantify soil microbial biomass (MB) and as biomarkers for bacteria, arbuscular mycorrhizal fungi (AMF), and saprophytic fungi (SF) which includes ectomycorrhizal fungi (ECM).ResultsNative grasslands had higher overall SOC and MB stocks in the top 300 cm soil depth (7.39 kg SOC m− 2 and 65.6 mmol MB m− 2) than converted cedar (6.80 kg SOC m− 2 and 38.4 mmol MB m− 2) or pine (5.87 kg SOC m− 2 and 39.9 mmol MB m− 2) forest. Losses of AMF biomass occurred on conversion of native grasslands to pine forest. Stocks of SF biomass only differed with vegetation type in topsoil.ConclusionsConversion of native grasslands to cedar or pine forest increased topsoil (0 − 10 cm) SOC storage due to needle litter accumulation. Conversion of native grasslands to forests decreased subsoil (10 − 300 cm) SOC stocks and had replaced, by increasing depth, 30 to 19% and 45 to 26% of grassland C with cedar and pine C, respectively. Changes in soil pH, nutrients, and soil microbial communities accelerated SOC turnover.

Coupling dendroecological and remote sensing techniques to assess the biophysical traits of Juniperus virginiana and Pinus ponderosa within the Semi-Arid grasslands of the Nebraska Sandhills

Woody species encroachment is occurring within the semi-arid grasslands of the Nebraska Sandhills U.S., primarily driven by native Juniperus virginiana and Pinus ponderosa, altering ecosystems and the services they provide. Effective, low cost, and cross-scale monitoring of woody species growth and performance is necessary for integrated grassland and forest management in the face of climate variability and change. In this study, we sought to establish a relationship between remote sensing-derived vegetation indices (VIs), tree dendrochronological (raw and standardized tree ring width) measurements, and the abiotic environment [(precipitation, temperature, Palmer Drought Severity Index (PDSI), and soil water content (0–300 cm depth)], over a 30-year period (1984–2013), to assess the performance of encroaching woody J. virginiana and P. ponderosa within the Nebraska Sandhills. We also investigated whether VIs can be used as an effective alternative tool to replace or complement ground measurements. Our results indicate that precipitation, temperature, and PDSI were significant (p < 0.05) predictors of J. virginiana and P. ponderosa growth based on dendrochronological measurements and VIs, while soil water content from 40 to 300 cm depth was a significant predictor of J. virginiana performance. Out of the six VIs that were investigated, four were significant predictors of tree ring growth. R2 values between grassland VIs and growing season climate were greater than those of J. virginiana or P. ponderosa, while grassland performance was decoupled from soil water content. Additionally, climatic conditions in the previous year were significant determinants of current year growth of tree species but did not affect current year grassland performance. This study provides evidence for the efficacy of remote sensing-based VIs in monitoring interannual variation in the growth of woody species, while determining abiotic factors impacting the growth of grassland vegetation, J. virginiana, and P. ponderosa in the Nebraska Sandhills.

Tree Trunk Detection of Eastern Red Cedar in Rangeland Environment with Deep Learning Technique

Uncontrolled spread of eastern red cedar invades the United States Great Plains prairie ecosystems and lowers biodiversity across native grasslands. The eastern red cedar (ERC) infestations cause significant challenges for ranchers and landowners, including the high costs of removing mature red cedars, reduced livestock forage feed, and reduced revenue from hunting leases. Therefore, a fleet of autonomous ground vehicles (AGV) is proposed to address the ERC infestation. However, detecting the target tree or trunk in a rangeland environment is critical in automating an ERC cutting operation. A tree trunk detection method was developed in this study for ERC trees trained in natural rangeland environments using a deep learning-based YOLOv5 model. An action camera acquired RGB images in a natural rangeland environment. A transfer learning method was adopted, and the YOLOv5 was trained to detect the varying size of the ERC tree trunk. A trained model precision, recall, and average precision were 87.8%, 84.3%, and 88.9%. The model accurately predicted the varying tree trunk sizes and differentiated between trunk and branches. This study demonstrated the potential for using pretrained deep learning models for tree trunk detection with RGB images. The developed machine vision system could be effectively integrated with a fleet of AGVs for ERC cutting. The proposed ERC tree trunk detection models would serve as a fundamental element for the AGV fleet, which would assist in effective rangeland management to maintain the ecological balance of grassland systems.

From Gain to Bane—and Back Again: What’s Next for Eastern Red Cedar?

CSA NewsVolume 68, Issue 6 p. 8-12 FEATURES From Gain to Bane—and Back Again: What’s Next for Eastern Red Cedar? Kristen Coyne, Kristen CoyneSearch for more papers by this author Kristen Coyne, Kristen CoyneSearch for more papers by this author First published: 29 May 2023 https://doi.org/10.1002/csan.21051Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Volume68, Issue6June 2023Pages 8-12 RelatedInformation

Authentication of Platycladus Orientalis Leaves and Its Five Adulterants by Combination of Morphology and Microscopic Characteristics, TLC, and HPLC Analysis.

Platycladus orientalis leaves (POL), as the source of the traditional Chinese medicine (TCM) Platycladi Cacumen, has frequently been found to be misused with five adulterants including Chamaecyparis obtusa leaves (COL), Cupressus funebris leaves (CFL), Juniperus virginiana leaves (JVL), Sabina chinensis leaves (SCL), and Juniperus formosana leaves (JFL). The purpose of this study was to distinguish POL (fresh leaves) from its five adulterants (fresh leaves). The micromorphological features in terms of transection and microscopic characteristics of POL and adulterants were captured and compared using the an microscope. Both HPLC and TLC methods for the simultaneous determination of six bioactive flavonoids (myricitrin, isoquercitrin, quercitrin, amentoflavone, afzelin, and hinokiflavone) have been developed. There were significant differences in microscopic features of transverse section and powders. The TLC results suggested that the spots of myricitrin in POL were more obvious than those in the five adulterants. The contents of myricitrin and quercitrin, or the total content of flavonoids in POL, determined by HPLC, were significantly higher than those in the adulterants. POL was successfully distinguished from its five adulterants by the comparison of morphology, microscopic characteristics, and chemical profiles. This research provides a comprehensive morphology, microscopic identification, TLC, and HPLC analysis for authenticating POL and its five adulterants.

Spatiotemporal patterns and environmental drivers of eastern redcedar (Juniperus virginiana) abundance along the Missouri River, USA

Changes in disturbance regimes, including reductions in flooding and geomorphic dynamism from dam construction and flow regulation, have facilitated invasion by eastern redcedar (Juniperus virginiana L.), an upland tree species, in the understory of floodplain forests along the Missouri National Recreational River (MNRR). Our aim was to determine the spatiotemporal patterns and environmental drivers of redcedar invasion along the MNRR. We used the Normalized Difference Vegetation Index (NDVI) calculated from winter Landsat imagery to construct a time series of maps showing spatial changes in redcedar abundance and distribution from 1982 to 2017 in both riparian and upland habitats along the MNRR. We determined how environmental factors (e.g., soil drainage ability, flood recurrence interval, 1980s LULC, lateral distance to the river, and channel incision) have influenced current (2017) redcedar occurrence and abundance in riparian habitats using random forest models (RFM). Time-series maps indicated that detectable redcedar cover occurred over less than 5% of the study area before 1985, increased steadily from 1985 to 2000, and more than tripled from 2000 to 2010. After 2010, redcedar abundance continued to increase in upland areas but declined following the 2011 Missouri River flood in the floodplain. RFMs indicated that river incision, distance to the river, soil drainage, 1984 LULC, and flood recurrence interval were important features influencing redcedar occurrence and abundance in the floodplain. Unless preventive measures are implemented, lack of floods and ongoing flow regulation will enable the continued spread of redcedar along the MNRR and other regulated rivers in the eastern Great Plains.

Eastern red cedar effects on carbon sequestration and soil quality in the Great Plains

AbstractEastern red cedar (ERC, Juniperus virginiana L.) is a common tree species in agroforestry plantings and has great potential for bioenergy production due to physical and chemical characteristics of its biomass. The objective of this study was to assess the effects of ERC plantings on carbon (C) sequestration and selected soil quality parameters in existing plantings across the northern U.S. Great Plains. Nine locations were selected in five states with mean annual precipitation (MAP) from 446 to 999 mm and mean annual temperature (MAT) from 4.4 to 10.0°C. Infiltration was measured using the twin ring technique at nine sites in each tree planting and adjacent field (crop, pasture, or hay) at each location. Following infiltration measurements, a 4.8 cm‐diameter soil core to 30 cm depth was collected from inside one infiltration ring of each pair for bulk density, pH, aggregate stability, soil organic carbon (SOC), and total nitrogen (TN) analyses. Penetration resistance in 2.5 cm increments to 30 cm depth was measured in the other infiltration ring. SOC stocks under ERC were significantly higher than in the adjacent field soil at five of the locations and, for all locations, averaged 16.8% greater than in the adjacent field. The estimated SOC accumulation rate for the eight locations with uniform tree stand age averaged 0.30 Mg C ha−1 year−1. Most locations had higher TN and C/N and lower bulk density beneath ERC. Fewer differences for infiltration and penetration resistance and smaller and less consistent differences for pH and aggregate stability were observed. Tree aboveground C stocks were estimated to increase an average of 2.05 Mg C ha−1 year−1. Estimated tree aboveground biomass C and SOC stocks under ERC and in adjacent fields were strongly correlated with MAP. Potential ERC planting for C sequestration or bioenergy feedstock production is not likely to significantly degrade soil quality and may improve soil physical or chemical quality for locations in the US Great Plains.

Investigating the effects of wind loading on three dimensional tree models using numerical simulation with implications for urban design

In this study, the effects of wind on an Eastern Red Cedar were investigated using numerical simulations. Two different tree models were proposed, each with varying bole lengths and canopy diameters. A total of 18 cases were examined, including different canopy diameters, bole lengths, and wind velocities. Using computational fluid dynamics (CFD) methods, the drag force, deformation, and stress of the tree models were calculated under different wind velocities and geometric parameters. A one-way fluid–structure interaction (FSI) method was used to solve the deformation of the tree. Additionally, velocity and pressure distribution around the tree were obtained. The results indicate that wind velocity and geometric parameters of the tree have a significant impact on deformation, drag force, and stress. As wind velocity increases from 15 to 25 m/s, the force on the tree increases substantially. The results also show that the diameter of the canopy has a bigger effect on stress and strain than the bole length. This study provides insights into tree behavior under wind loading for urban planning and design, informing optimal tree selection and placement for windbreak effectiveness and comfortable environments.

Woody plant encroachment in granite barrens on the Frontenac Arch, eastern Ontario, Canada

AbstractAimsWoody plant encroachment is a widespread phenomenon affecting treeless or sparsely treed habitats. We aimed to determine the extent and timing of tree and shrub encroachment into rock barrens of eastern Ontario over the last century, and to assess implications for their ongoing management.LocationQueen's University Biological Station in the Frontenac Arch ecoregion.MethodsWe quantified the extent of change in woody vegetation in 290 rock barrens using aerial photography from 1925, 1965, and 2008. Composition and structure of woody plant communities in 10 barrens was subsequently quantified in the field using plot‐based sampling. Cores or cross‐sections were obtained from individuals &gt;1.5 m height and dendrochronological techniques were used to determine their age and identify temporal patterns of any woody encroachment.ResultsAerial photography indicated that the mean proportion of woody plant cover in barrens increased 22.5% from 1925 to 2008. Dendroecological analysis supported this. Few trees were present prior to 1900 and most established since 1960.Fraxinus americana,Juniperus virginiana, andJuniperus communiswere the most common woody species colonizing the barrens. Remnants of largePinus strobusstumps with extensive charring were found in 90% of the sampled barrens at a mean density of 22.6 stumps ha−1.ConclusionsRock barrens on the Frontenac Arch have changed substantially over the past century; gradually being colonized by trees and shrubs and losing their distinctly open character. Active management — including prescribed fire and mechanical thinning — may be necessary if there is a desire to maintain these barrens and the rare species they support as components of the region's biodiversity. However, identification of a reference state for restoration is complicated by the fact that the structure and composition of these habitats were undoubtedly altered by European land clearance in the 19th century, and that some of these areas likely existed as pine woodlands before that.

Anticancer Podophyllotoxin Recovery from Juniper Leaves at Atmospheric and High Pressure Using Eco-Friendly Solvents

Podophyllotoxin (PPT) is a precursor for the synthesis of drugs against cancer and other diseases. The present sources of PPT (Sinopodophyllum hexandrum and Podophyllum peltatum) are endangered species, with PPT production highly dependent on their growing conditions. In connection with the identification of new sources of PPT, the present study aimed to recover PPT from Juniperus virginiana leaves via atmospheric or high pressure extraction methods with a focus on using eco-friendly solvents. PPT quantification was determined by UHPLC/HRMS/MS. A thorough study of conventional extraction was carried out to reveal the optimal conditions (solvent ethyl acetate at room temperature and a duration of 1 h) for maximizing the PPT recovery (about 30 mg/g of dry extract and 3 mg/g of dry initial plant material). Peleg's equation was applied for process kinetics modeling. The best PPT content in the final dry extract (42-45 mg/g of dry extract) was obtained by high pressure methods under supercritical (scCO2 with ethanol or ethyl acetate, 30 MPa, 50 °C and 100 min) or accelerated solvent extraction conditions (solvent ethyl acetate, 10.35 MPa, 20 °C and 3 cycles for 15 min). Seasonal stability and storage stability of the raw material were also determined. The present results have potential applications in the pharmacy for the delivery of PPT from juniper leaves.

Goat Defoliation and Debarking on Eastern Redcedar with Rumen Undegradable Protein Supplement

Eastern redcedar (ERC) (Juniperus virginiana L.) encroachment threatens long-term Great Plains health. Goats browse juniper by defoliation and debarking but are limited by aversive postingestive feedback from plant secondary metabolites. Protein supplementation may increase fed juniper foliage intake by offsetting nitrogen loss from plant secondary metabolites−protein binding, but little is known for goats browsing whole juniper, mimicking a field setting. Therefore, the objective was to study the effects of rumen undegradable protein (RUP) supplementation and tree height on goat browsing. Experimental design was two 3 × 3 Latin squares of two diets and three ERC tree height treatments. Within each square, 12 Savannah × Spanish × Boer crossbred 50 kg ± 3.9 kg does were fixed to a diet for 10 d (7 d adaptation and 3 d ERC browsing). Fed diets were control (grass hay and whole corn) and supplemented (grass hay and dried distiller's grain, an RUP source). Diets were isocaloric, and supplemented diet crude protein was fed at 2 × maintenance. Each pen (three pens of four goats per diet) was offered two trees from one of three tree height treatments for 8 h daily over 3 d in a rotation where pens received all tree height treatments. Supplemented RUP did not increase defoliation (P = 0.73), trunk debarking (P = 0.84), or branch browsing (P = 0.74). However, tree height may impact browsing as short (50 cm) trees were more defoliated and 50 cm and 100 cm trees had more branches browsed than taller (200 cm) trees (P < 0.05). Therefore, for field application relevance, it may be more important for pen studies to measure browsing of whole juniper rather than fed foliage intake. Future pen and/or field studies should explore alternative protein sources, consider tree height in their design, and offer goats whole juniper.

Comparative toxicity of essential oils, their emulsifiable concentrates and nanoemulsion formulations against the bean aphid, Aphis fabae

The present study aims to prepare emulsifiable concentrate (EC) and nanoemulsion formulations from the plant essential oils of Lavandula angustifolia (Mill.), Ambrosia maritima (L.), Commiphora myrrha (Nees) Engl., Juniperus virginiana (L.), Rheum palmatum (L.) and Tagetes minuta (L.). The efficiency of these essential oils along with their formulations were compared against the bean aphid, Aphis fabae (Scopoli). Results disclosed that all EC preparations passed the emulsion stability and foam formation tests. The particle droplet size of the nanoemulsions varied from 64.3 to 264.7 nm. The toxicity of EC formulations was slightly higher than the corresponding nanoemulsion formulations. Both EC and nanoemulsion of R. palmatum were the most efficient (LC50 = 1003.60 and 1105.34 mg L−1, respectively). EC preparations had no adverse effects on seed beans. The absence of organic solvents and the high aphicidal activity of EC formulations might make these preparations suitable for controlling A. fabae.

The rapid-tome, a 3D-printed microtome, and an updated hand-sectioning method for high-quality plant sectioning

BackgroundMicroscopic analysis of plant anatomy is a common procedure in biology to study structure and function that requires high-quality sections for accurate measurements. Hand sectioning of specimens is typically limited to moderately soft tissue while harder samples prohibit sectioning by hand and/or result in inconsistent thicknesses.ResultsHere we present both a clearly described hand-sectioning method and a novel microtome design that together provide the means to section a variety of plant sample types. The described hand-sectioning method for herbaceous stems works well for softer subjects but is less suitable for samples with secondary growth (e.g., wood production). Instead, the “Rapid-Tome” is a novel tool for sectioning both soft and tougher high-aspect-ratio samples, such as stems and roots, with excellent sample control. The Rapid-Tome can be 3D-printed in approximately 18 h on a mid-quality printer common at university maker spaces. After printing and trimming, Rapid-Tome assembly takes a few minutes with five metal parts common at hardware stores. Users sectioned a variety of plant samples including the hollow internodes of switchgrass (Panicum virgatum), fibrous switchgrass roots containing aerenchyma, and woody branches of eastern red cedar (Juniperus virginiana) and American sycamore (Platanus occidentalis). A comparative analyses with Rapid-Tome-produced sections readily revealed a significant difference in seasonal growth of sycamore xylem vessel area in spring (49%) vs. summer (23%). Additionally, high school students with no prior experience produced sections with the Rapid-Tome adequate for comparative analyses of various plant samples in less than an hour.ConclusionsThe described hand-sectioning method is suitable for softer tissues, including hollow-stemmed grasses and similar samples. In addition, the Rapid-Tome provides capacity to safely produce high-quality sections of tougher plant materials at a fraction of the cost of traditional microtomes combined with excellent sample control. The Rapid-Tome features rapid sectioning, sample advancement, blade changes, and sample changes; it is highly portable and can be used easily with minimal training making production of thin sections accessible for classroom and outreach use, in addition to research.

Effects of post oak (Quercus stellata) and smooth brome (Bromus inermis) competition on water uptake and root partitioning of eastern redcedar (Juniperus virginiana).

Eastern redcedar Juniperus virginiana is encroaching into new habitats, which will affect native ecosystems as this species competes with other plants for available resources, including water. We designed a greenhouse experiment to investigate changes in soil moisture content and rooting depths of two-year-old J. virginiana saplings growing with or without competition. We had four competition treatments: 1) none, 2) with a native tree (Quercus stellata), 3) with an invasive grass (Bromus inermis), and 4) with both Q. stellata and B. inermis. We measured soil moisture content over two years as well as root length, total biomass, relative water content, midday water potential, and mortality at the end of the experiment. When J. virginiana and B. inermis grew together, water depletion occurred at both 30-40 cm and 10-20 cm. Combined with root length results, we can infer that J. virginiana most likely took up water from the deeper layers whereas B. inermis used water from the top layers. We found a similar pattern of water depletion and uptake when J. virginiana grew with Q. stellata, indicating that J. virginiana took up water from the deeper layers and Q. stellata used water mostly from the top soil layers. When the three species grew together, we found root overlap between J. virginiana and Q. stellata. Despite the root overlap, our relative water content and water potential indicate that J. virginiana was not water stressed in any of the plant combinations. Regardless, J. virginiana saplings had less total biomass in treatments with B. inermis and we recorded a significantly higher mortality when J. virginiana grew with both competitors. Root overlap and partitioning can affect how J. virginiana perform and adapt to new competitors and can allow their co-existence with grasses and other woody species, which can facilitate J. virginiana encroachment into grasslands and woodlands. Our data also show that competition with both Q. stellata and B. inermis could limit establishment, regardless of water availability.