Juniperus Species Research Articles

Comparative Antioxidant Properties of Juniperus communis L. and Juniperus virginiana L. Extracts Obtained by Refluxing and Sonication Methods

The aim of this study was to evaluate the antioxidant activity of ethyl acetate and tetrahydrofuran extracts of Juniperus berries, branches and needles, by using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Two Juniperus species, Juniperus communis and Juniperus virginiana, from different regions were used. The extracts obtained by sonication and refluxing extraction were studied by gas chromatography-mass spectrometry, which revealed that the Romanian juniper extracts are largely comprised of monoterpene hydrocarbons, such as a-pinene, b-pinene, b-hellandrene, sabinene, b-cadinene, t-cadinene, b-caryophyllene, b-cubebene, b-elemene and germacrene D. The antioxidant activity was highest in ethyl acetate Juniperus communis needles extract from Lipova (Romania) and in ethyl acetate Juniperus virginiana branches extract from Macea Botanical Garden (Romania). The mean rates (vm) of DPPH consumption were higher for the tetrahydrofuran Juniperus communis branches extract from Lipova and ethyl acetate Juniperus virginiana branches extract than in tetrahydrofuran Juniperus communis berries extract from Lipova.

Promoting natural regeneration for the restoration of Juniperus communis: a synthesis of knowledge and evidence for conservation practitioners

AbstractQuestionsNatural regeneration is central to plant conservation strategies. Worldwide, many Juniperus species are threatened due to their failure to regenerate. We focus on Juniperus communis in areas of NW Europe where it is declining and ask: what advice is available to land managers on natural regeneration methods, and when applied, how effective has this been?MethodsWe synthesize knowledge on the efficacy of management interventions and conditions associated with J. communis regeneration. In field trials, we test interventions where knowledge is lacking. We assess regeneration of J. communis, creation of regeneration microsites and germination of sown seed in response to the interventions.ResultsAlthough J. communis occurs in different habitats, there is consistency in site conditions important for regeneration (unshaded/open, short ground vegetation, disturbed/bare ground, low herbivore pressure). In calcareous grasslands, areas with regeneration are stony/bare or vegetation is short or sparse; in upland acid grasslands and dry heathlands regeneration locations are disturbed areas sometimes with a moss cover. Several interventions (grazing, scarification, turf stripping) can create regeneration conditions. The synthesis identified cattle grazing and ground scarification for further testing on upland acid grasslands. In the resulting field trials, regeneration was rare and recorded on only one cattle‐grazed site. An exposed moss layer characterized regeneration microsites but there was insufficient evidence that either intervention increased regeneration microsite frequency. Few sown seeds germinated.ConclusionsDifferent interventions or intensities of these appear to be required depending on habitat type. Broadly, on calcareous grassland intense scarification or soil stripping is needed, while on dry heathlands light scarification is suitable. On upland acid grassland, cattle grazing and ground scarification do not reliably result in regeneration. Creation of favourable mossy regeneration microsites is unlikely following intervention, unless soil fertility is low. Land‐use change, increased climate warming and pollution are pressures acting on J. communis and may cause habitat loss and altered site conditions (e.g. soil fertility), making it difficult to create regeneration microsites at all J. communis sites. Other constraints on regeneration may operate (e.g. seed predation and low seed viability) and managers should assess population and site potential before undertaking management.

Different parts of the same plants. Charcoals and seeds from Cova de les Cendres (Alicante, Spain)

The analysis of archaeobotanical macroremains from Cova de les Cendres (Teulada-Moraira, Alicante, Spain) allows a better understanding of the dynamic of the vegetation during the Upper Palaeolithic in the region. The anthracological sequence shows that Pinus type nigra/sylvestris dominates in the area during the Upper Palaeolithic, while more open formations of Juniperus and Fabaceae spread in Upper Solutrean and Early-Middle Magdalenian. The carpological analysis that has been carried out in the Middle Magdalenian level has brought to light different species of Juniperus (J. sabina, J. communis and J. oxycedrus). This information indicates that during the period, Cova de les Cendres had similar bioclimatic conditions to those currently prevailing in the Iberian summits of the supramediterranean belt. New 14C dates obtained from Juniperus sabina and Buglossoides cf. arvensis seeds as well as from charcoal fragments of Ephedra sp., presented in this paper, prove the existence of steppe landscapes during the Late Glacial.

Comparative Analysis of Chemical Profile, Antioxidant, In-vitro and In-vivo Antidiabetic Activities of Juniperus foetidissima Willd. and Juniperus sabina L.

Fruit and leaves of junipers are commonly used internally as tea and pounded fruits are eaten to lower blood glucose levels in Anatolia. Thus, we aimed to evaluate antidiabetic and antioxidant potential and the chemical profile of Juniperus foetidissima Willd. and J. sabina L. in this study. In-vitro antidiabetic activities of leaf and fruit extracts were examined by their inhibitory activity on α-glucosidase and α-amylase enzymes. Then, in-vivo antidiabetic activities of leaf and fruit extracts of Juniperus species were investigated on streptozotocin-induced diabetic rats. Additionally, antioxidant activities (phosphomolybdenum, ferric-reducing antioxidant power and ABTS radical scavenging activity assays), phytochemical screening tests and high performance liquid chromatography analysis (HPLC) were done. In-vitro enzyme inhibitory effects of the extracts were supported by the results of in-vivo antidiabetic activity studies. Phytochemical screening tests indicated presence of flavonoids, tannins, terpenoids and carbohydrates in the extracts. Amentoflavone was identified as the major compound in the extracts and content of amentoflavone was determined. As a result, Juniperus extracts and its active constituents might be beneficial for diabetes and its complications.

Essential Oil Content, Composition and Bioactivity of Juniper Species in Wyoming, United States

The objective of this study was to evaluate variations in leaf essential oil (EO) content and composition of Juniperus species in the Bighorn Mountains {J comimunis L. (common juniper), J. horizontalis Moench. (creeping juniper), and J scopulorum Sarg. (Rocky Mountain juniper)} in Wyoming, USA. The EO was extracted via steam distillation of fresh leaves (needles). The EO composition of the three Juniper species varied widely. Overall, the essential oil content of fresh leaves was 1.0% (0.4-1.8% range in different accessions) in J. communis, 1.3% (1.2 to 1.6% range) in J. horizontalis, and 1.1% (0.7-1.5% range) in J. scopulorln. The EO chemical profile of J. communis was very different from that of the other two species. The concentration of α-pinene in the oil was 67- 80% in J. communis, 2.8-6% in J. horizontalis, and 2.3-13% in J. scopulorun. The concentration of sabinene was 57-61% of the oil of J. horizontalis and 13- 59%. in oil of J. scopulorum, whereas sabinene was either below 1% or not detected in J. communis. The oils of J scopulorm and J horizontalis had higher antioxidant capacity than that of J. communis. The oils of the three junipers did not show significant antimicrobial activity against 10 organisms. The diversity of the essential oil composition of these three junipers may encourage diverse industrial applications of Juniperus leaf essential oil.

Étude de la variabilité morphologique (aiguilles, galbules) du complexe spécifique Juniperus oxycedrus l., le Genévrier oxycèdre, au sein de sept populations d’Algérie

Morphological variability (needles, galbulus) among seven populations of the Juniperus oxycedrus L. species-complex in Algeria. The comparative study of plant polymorphism using plant taxonomic characters is underrated in Algeria, especially for species of the genus Juniperus L. The present work has been realized in order to look out for the existence of phenotypic variability among seven natural populations of Juniperus oxycedrus L. through a descriptive and comparative analysis of the needles, galbulus and stomata. The epidermal surfaces have also been investigated in order to better characterize this species. Twenty-three quantitative and qualitative morphological characters have been studied. The observation and evaluation of macro and micro-morphological characters have been realized with binocular optical and scanning electronic microscopes. The variance analysis showed that the seven studied populations present a considerable morphological diversity at both intra-and inter-population levels for the variables needles, galbulus and stomata, while the multivariate analysis allowed to separate all the studied populations into distinct groups according to their phenotypic characters, highlighting correlations between the morphological variables and the environmental characteristics. Otherwise, micro-morphological variations have been observed for the epidermal surfaces including a variation in the stomatal density, the size of stomata, the occurrence of epicuticular wax and changes in the epidermal structure.

Hepatoprotective and nephroprotective activities of Juniperus sabina L. aerial parts

Context: Previous studies indicated that Juniperus species exhibited promising hepatoprotective activity. Aims: To evaluate the hepatoprotective and nephroprotective activity of the total alcohol extract of the aerial parts of Juniperus sabina against carbon tetrachloride (CCl4) induced toxicity using male Wistar rats as experimental animals. Methods: Daily oral administration of two doses (200 and 400 mg/kg) of the total extract of the aerial parts of J. sabina for seven days followed by one dose of CCl4 (1.25 mL/kg) at day 6. Liver and kidney functions were monitored via measuring serum and tissue parameters as well as histopathological study. Normal rats, rats treated only with CCl4 and rats treated with CCl4 and silymarin were used as controls. Results: The higher dose showed 47, 50, 38, 17 and 42% decrease in the levels of AST, ALT, GGT, ALP, and bilirubin respectively. Animals received the total extract of J. sabina showed a significant dose-dependent recovery of the NP-SH contents, total proteins, and reduction the level of MDA in both liver and kidney tissues. Histopathological study revealed improvement in the architecture of hepatocytes and kidney cells. Conclusions: The hepatoprotective effect offered by J. sabina crude extract at the two used doses was found to be significant in all serum parameters. Histopathological study revealed moderate improvement in the architecture of the liver cells that add another indication of protection. Improvement of kidney function was less than liver function.

Molecular approaches for the analysis of airborne pollen: A case study of Juniperus pollen

BackgroundPollen monitoring is a common and vital tool in the field of allergy, creating awareness in pollen sensitive individuals. Traditionally, pollen monitoring has been based on conventional microscopic counting techniques that are labor intensive and limited in the identification to the genus or family level. Molecular techniques provide an alternative approach that is less labor intensive and enable identification of any species by its genetic fingerprint. ObjectiveTo use quantitative polymerase chain reaction (qPCR) to evaluate pollen concentrations in air samples. MethodsJuniperus pollen was selected as our model because of the importance of this pollen in the southcentral United States. We analyzed 105 air samples collected with a Burkard spore trap from 2013 to 2015 using species-specific primers and probes. To evaluate the feasibility of a molecular approach, we used duplicate air samples that allowed us to compare results from classical identification based on light microscopy with our qPCR results. ResultsPollen concentrations from the qPCR data were significantly correlated with concentrations determined through light microscopy (R = 0.902, P < .001). We also confirmed an overlap in the pollination seasons between Juniperus ashei and Juniperus pinchotii and between J ashei and Juniperus virginiana. ConclusionWe found that this method correctly identified different Juniperus species present in mixed air samples in the southcentral United States, an accomplishment that cannot be achieved using microscopic identification. We conclude that the qPCR method is more accurate and sensitive than current pollen monitoring techniques and, therefore, has the potential to be used in various pollen monitoring stations.

Ecophysiological responses of native invasive woody Juniperus virginiana L. to resource availability and stand characteristics in the semiarid grasslands of the Nebraska Sandhills

Vegetation in grasslands is changing at an unprecedented rate. In the Nebraska Sandhills, this shift is attributed in part to encroachment of the woody species Juniperus virginiana. We investigated changes in resource availability and their feedback on seasonal trends in photosynthetic characteristics of J. virginiana trees scattered in open grasslands vs. a dense 57-year-old stand. Dense stand exhibited lower volumetric soil water content, NH4+, NO3–, and δ13C, as well as foliage δ13C, δ15N, and N content, compared to grasslands. Water potential was higher in trees in grasslands compared to dense stand. J. virginiana in dense stand exhibited similar trends to trees in grasslands for net photosynthetic rate (PN), stomatal conductance, transpiration, maximum photochemical efficiency of PSII, maximum carboxylation velocity, and maximum rate of electron transport. PN peaked early summer and declined in the fall, with trees in open grasslands lagging behind those in dense stand. Plasticity of this species may place it at a competitive advantage in the Sandhills, further altering grasslands vegetation and ecosystem processes.

Investigation of the Lignan Content in Extracts from Linum, Callitris and Juniperus Species in Relation to Their In Vitro Antiproliferative Activities.

Podophyllotoxin, a lignan still extracted from the rhizomes of Podophyllum hexandrum (Berberidaceae), is the starting molecule for the semisynthesis of widely used anticancer drugs such as etoposide. However, this source is threatened by the over-collection of P. hexandrum. Plants belonging to the Linaceae and Cupressaceae families could be attractive alternative sources with species that contain the lignan podophyllotoxin or its precursors and derivatives. Wild flax species, such as Linum flavum, as well as some Juniperus and Callitris species were investigated for their lignan content, and the in vitro antiproliferative capacity of their extracts was assayed on four tumor cell lines. Some of the lignans were detected by LC-HRMS for the first time in these extracts.In addition, lignans purified from these plants and compounds semisynthesized from commercially available podophyllotoxin were tested in terms of their in vitro antiproliferative activity. The genus Juniperus was the most promising given its in vitro antiproliferative effects, which were also observed with extracts from L.flavum and Callitris species.The in vitro antiproliferative effect of the plant extracts studied here appears to correlate well with the contents of the aryltetralin lignan podophyllotoxin and its glycoside as well as with deoxypodophyllotoxin and 6-methoxypodophyllotoxin. The strongest correlation between the lignan content of the extracts and the antiproliferative activity was observed for 6-methoxypodophyllotoxin. Regarding the possibility of producing large renewable amounts of 6-methoxypodophyllotoxin, this molecule could be of interest to produce new anticancer drugs and to bypass the resistance mechanisms against podophyllotoxin-derived drugs.

Inferring phylogeny and speciation of Gymnosporangium species, and their coevolution with host plants.

Gymnosporangium species (Pucciniaceae, Pucciniales) cause serious diseases and significant economic losses to apple cultivars. Most of the reported species are heteroecious and complete their life cycles on two different plant hosts belonging to two unrelated genera, i.e. Juniperus and Malus. However, the phylogenetic relationships among Gymnosporangium species and the evolutionary history of Gymnosporangium on its aecial and telial hosts were still undetermined. In this study, we recognized species based on rDNA sequence data by using coalescent method of generalized mixed Yule-coalescent (GMYC) and Poisson Tree Processes (PTP) models. The evolutionary relationships of Gymnosporangium species and their hosts were investigated by comparing the cophylogenetic analyses of Gymnosporangium species with Malus species and Juniperus species, respectively. The concordant results of GMYC and PTP analyses recognized 14 species including 12 known species and two undescribed species. In addition, host alternations of 10 Gymnosporangium species were uncovered by linking the derived sequences between their aecial and telial stages. This study revealed the evolutionary process of Gymnosporangium species, and clarified that the aecial hosts played more important roles than telial hosts in the speciation of Gymnosporangium species. Host switch, losses, duplication and failure to divergence all contributed to the speciation of Gymnosporangium species.

Vegetation patch dynamics and tree diversity in a diverse conifer and oak forest in central Mexico

Mexican conifer and oak forests are very diverse, and represent the vegetation type with the highest timber production in Mexico. Yet, there is little knowledge about the relationship of forest recovery and tree diversity in this type of vegetation. In this study, we analyzed the dynamics of vegetation patches over three time periods covering five decades, within an area in central Mexico dominated by conifer and oak forest. We identified vegetation patches, and evaluated their number and changes in patch size and vegetation cover. We also evaluated the composition and structure of the plant canopy in vegetation plots representing different canopy cover classes. Over the three periods studied, the number and total area of patches remained relatively constant, but an increase in canopy vegetation cover occurred in most vegetation patches. Patch canopies were dominated by the long-lived pioneer tree species Juniperus deppeana and the shrub Arctostaphylos pungens . We suggest that forest management in our study region should focus on facilitating the dominance of pines and oaks in sites that have recovered their canopy cover, and to identify the factors inhibiting succession in patches with less than 10 % vegetation cover.

Insights from the pollination drop proteome and the ovule transcriptome ofCephalotaxusat the time of pollination drop production

Many gymnosperms produce an ovular secretion, the pollination drop, during reproduction. The drops serve as a landing site for pollen, but also contain a suite of ions and organic compounds, including proteins, that suggests diverse roles for the drop during pollination. Proteins in the drops of species of Chamaecyparis, Juniperus, Taxus, Pseudotsuga, Ephedra and Welwitschia are thought to function in the conversion of sugars, defence against pathogens, and pollen growth and development. To better understand gymnosperm pollination biology, the pollination drop proteomes of pollination drops from two species of Cephalotaxus have been characterized and an ovular transcriptome for C. sinensis has been assembled. Mass spectrometry was used to identify proteins in the pollination drops of Cephalotaxus sinensis and C. koreana RNA-sequencing (RNA-Seq) was employed to assemble a transcriptome and identify transcripts present in the ovules of C. sinensis at the time of pollination drop production. About 30 proteins were detected in the pollination drops of both species. Many of these have been detected in the drops of other gymnosperms and probably function in defence, polysaccharide metabolism and pollen tube growth. Other proteins appear to be unique to Cephalotaxus, and their putative functions include starch and callose degradation, among others. Together, the proteins appear either to have been secreted into the drop or to occur there due to breakdown of ovular cells during drop production. Ovular transcripts represent a wide range of gene ontology categories, and some may be involved in drop formation, ovule development and pollen-ovule interactions. The proteome of Cephalotaxus pollination drops shares a number of components with those of other conifers and gnetophytes, including proteins for defence such as chitinases and for carbohydrate modification such as β-galactosidase. Proteins likely to be of intracellular origin, however, form a larger component of drops from Cephalotaxus than expected from studies of other conifers. This is consistent with the observation of nucellar breakdown during drop formation in Cephalotaxus The transcriptome data provide a framework for understanding multiple metabolic processes that occur within the ovule and the pollination drop just before fertilization. They reveal the deep conservation of WUSCHEL expression in ovules and raise questions about whether any of the S-locus transcripts in Cephalotaxus ovules might be involved in pollen-ovule recognition.

Seasonal variation and bioactivity of the essential oils of two Juniperus species against Aedes (Stegomyia) albopictus (Skuse, 1894).

The seasonal variation in respect to the yield and chemical composition of 24 essential oils (EOs) isolated from various parts (leaves and fruits) of two indigenous Greece Juniperus species (family Cupressaceae), namely Juniperus drupacea and Juniperus phoenica, were determined by GC and GC/MS analysis. The larvicidal properties of these EOs were evaluated against 3rd and early 4th instar larvae of Aedes (Stegomyia) albopictus (Skuse, 1894) at one screening dose (29mgL(-1)). Moreover, the repellent activity against adult mosquitoes was also evaluated at one screening dose. The analytical data indicated that the EOs mainly consisted of monoterpenes, mostly cyclic and only occasionally aliphatic and to a lesser percent diterpenes. The EOs yield was sharply increased when the plant material was subjected to pre-treatment before steam distillation. Finally, the influence of plant material collection period on their yield and chemical content was also determined. Bioactivity assessments indicated that three EOs possess very potent larvicidal properties and 12 EOs display significant repellent activities since they were proved to be "DEET-like." Therefore, they represent an inexpensive source of natural mixtures of larvicidal and repellent mixture of natural compounds, with potentials for application for utilization in mosquito control schemes in order to prevent the expansion of viral infections.

English

In the present study, in vitro bioassay screening of total methanolic extracts of two Juniperus species (Juniperus horizontalis Moench. and Juniperus communis L.) cultivated in Egypt for schistosomicidal and molluscicidal activities was carried out. Schistosoma mansoni Sambon worms and Biomphalaria alexandrina (Ehrenberg) snails were used. The screening results showed that both tested extracts had almost similar schistosomicidal activity (LC50 &asymp; 91 &micro;g/ml, in 3 days) while J. communis extract possess more potent molluscicidal activity than J. horizontalis (LC50 = 22.9 and 38.9 ppm, after one day, respectively). Analysis of the chemical composition of the essential oils obtained by hydro-distillation of the aerial parts of the two Junipers species was done by GC/MS. Sixty seven (94.32%) components were identified in J. communis oil with homogeraniol (36.95%) being the major constituent, while sixty (95.39%) components were identified in J. horizontalis oil with the main component, bronyl acetate representing 41.17%. Key words: Essential oils, Juniperus, molluscicidal, schistosomicidal.

Rapid Quantification of Juniperus Pollen Proves Overlapping Pollen Seasons

Rashmi Prava Mohanty, Mark A. Buchheim, PhD, Estelle Levetin, PhD, FAAAAI; University of Tulsa, Tulsa, OK, University of Tulsa. RATIONALE: Microscopic analysis of air samples fails to determine the pollination season overlap between various species with morphologically similar pollen such as members of the Cupressaceae and Poaceae. Previously, we showed it was possible to use PCR to identify Juniperus ashei pollen from air samples. The present study was undertaken to determine if qPCR could be used to determine airborne pollen counts for three Juniperus species and define the pollination season overlap. METHODS: The atmosphere in Tulsa, OK(USA) was monitored with a Burkard sampler and analyzed by microscopy using standard methods. A second Burkard sampler was used from 2013 to 2015 for molecular analysis; 109 samples were tested with species-specific primers and probes designed for J.ashei, J.pinchotii and J.virginiana. Numbers of pollen grains obtained from microscopy were compared with numbers obtained from qPCR by Spearman correlation coefficient. RESULTS: Cupressaceae pollen was detected in the Tulsa atmosphere from October through April. The qPCR counts for total Juniperus pollen showed a significant correlation with the microscope counts, R50.92, p<0.001. Quantitative PCR data showed overlapping pollen seasons. In the fall, data indicated five days (in two years) with both J.pinchotii and J.ashei pollen. Similarly, in January and February eight days (in two years) indicated both J.ashei and J.virginiana pollen in the air. CONCLUSIONS: This approach is a rapidmethod to identify and quantify specific pollen types and the pollen season overlap where species and genera cannot be distinguished by microscopy. Defining the exact pollination season will be a benefit for patients sensitive to pollen from specific taxa.

Impacts of participatory forest management on species composition and forest structure in Ethiopia

ABSTRACTThe present study assesses the impacts of decentralized forest management on forest conditions in Ethiopian Montane forests. We compared observed densities of different tree species and size categories in forests managed by local forest user groups (FUGs) and the government. We used forest inventory data from 23,046 ha of contiguous forest managed by 74 individual FUGs. Topographical variables, including altitude, slope and aspect, were retrieved from Digital Elevation Model data for each FUG polygon. Generalized additive models and matching models were employed to analyse the effects of management and eliminate confounding factors. Findings show that altitude and slope were the topographical variables that had the strongest influence on species distribution. The overall densities of mature trees ha−1 and four individual species (Afrocarpus falcatus, Schefflera abyssinica, Hypericum lanceolatum and Rapanea melanophloeos) were higher in forests under participatory management (p < 0.01). The three major commercial timber species Juniperus excelsa, Afrocarpus falcatus and Hagenia abyssinica constituted 49% of the total relative density and 39% the total relative frequency. In spite of the fact that inventories were carried out only 3–5 years after the forests had been handed over to FUGs, the observed patterns in vegetation density indicate that participatory management was more successful than government management in making forestry sustainable.EDITED BY Carsten Smith-Hall

The effect of altitude on the presence of plant species in stands for Juniperus L. plant species on Kopaonik

In this paper we present an assessment of the altitude effect on the plant species presence in different plant communities - the species of Juniperus genus (Juniperus communis L., Juniperus oxycedrus L. and Juniperus sibirica Burgsdorf) on Kopaonik Mountain. Two juniper species (Juniperus communis and Juniperus oxycedrus) were recorded at altitudes ranging from 420 m to 1420 m, while the third species Juniperus sibirica was found at an altitude of 2100 m. It was determined that the plant communities with the presence of species of the Juniperus genus differ in botanical terms at different altitudes. It was found that there are plant species in certain communities that are present only at some altitudes, while others were present at almost all altitudes. The species of Hypericum perforatum L. is recorded in all of plant communities surveyed that proves its best adaptation to the conditions at different altitudes.

Dynamics of frost tolerance during regeneration in a mixed (pine–oak–juniper) Mediterranean forest

Key message The effect of unexpected low tempera- ture on coexisting species in inland locations was examined; frost tolerance simulation over a 2-year period was used to determine bottlenecks where com- petition can arise. Abstract The effect of frost events on natural regenera- tion of Mediterranean mixed forests under a scenario of climate change is not well known. The expected increase in mean annual temperature and the greater inter- and intra- annual variability in frosts occurrence can significantly damage natural regeneration leading to death, with a decisive effect on species composition and forest dynam- ics. We investigated seasonal variations in frost tolerance of three Mediterranean species (Pinus pinea, Quercus ilex and Juniperus oxycedrus) co-occurring in inland locations in Spain. Our aim was to assess seasonal inter-specific differences in frost sensitivity or tolerance. First, we applied the relative electrolyte leakage method (REL) to estimate the frost tolerance of these species every 3-4 weeks during the 9-month period in which frost events can occur in a year. Second, we explored the REL rela- tionship with environmental variables impacting frost acclimation/deacclimation, i.e., absolute minimum and maximum temperatures and photoperiod. Third, we built a REL model to predict seasonal variations in REL perfor- mance of young trees. We simulated REL through a 2-year period, thus defining seasonal bottlenecks in which the dynamics of regeneration can be affected by frost events. Our results showed contrasting behaviors between species, highlighting a greater sensitivity to cold of P. pinea com- pared to the other two species. The three species are most vulnerable in autumn; however, the different strategies to cope with unfavorable conditions adopted by Q. ilex and J. oxycedrus (e.g., stress tolerance and/or resprouting ability) give these species a competitive advantage over P. pinea.

Effects of Juniperus species and stage of maturity on nutritional, in vitro digestibility, and plant secondary compound characteristics.

Rising feed costs and recurring feed shortages necessitate the investigation into alternative and underutilized feed resources. Nutritional characteristics of species are either unknown or limited to leaves and ground material from small stems. Therefore, the objective was to quantify nutritional characteristics, 48-h true IVDMD (tIVDMD), microbial gas production, and secondary compound characteristics of entire woody plant material of 4 species-, , , and -at immature and mature stages of growth. Immature plants had greater CP concentrations and lower NDF concentrations ( < 0.001) than mature plants regardless of species. Mature plants also had greater ( < 0.001) concentrations of ADF compared with immature plants with the exception of . In general, immature , , and had greater ( < 0.02) tIVDMD and total 48-h and asymptotic gas production than mature plants. Immature and plants were more digested (tIVDMD; < 0.001) than immature and , but tIVDMD did not differ in mature plant material across species. Condensed tannins (CT) were greater ( < 0.001) in immature and than mature plants; differences in CT concentrations among immature species were also detected ( < 0.04). Volatile oil yields were similar across maturity and species with 1 exception: immature yielded more ( < 0.02) volatile oil than mature material. Volatile oil composition across species varied and contained a range of 65 to 70 terpene compounds. The dominant terpenes across species were generally greater ( < 0.05) in immature vs. mature plant material with the exception of . Labdane acids were negligible in , , and and greater in ( < 0.001). Ground material from mature juniper species, although inferior in nutritional quality compared with immature plants, is comparable to traditional low-quality roughage ingredients. Given that has been successfully fed in lamb feedlot diets, the similarities of , and suggest that all three species have potential to be effective roughage ingredients.