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1.
This study was performed to investigate the constituents, in vitro antifungal activity and phytotoxicity potential of the essential oil from Juniperus polycarpos var. turcomanica leaves. The essential oil was analyzed by GC–FID, and GC/MS, which predominantly contains α-pinene (51.21%), germacrene–B (4.80%), and ∆-cadinene (2.56%). The antifungal activity of the essential oil against some phytopathogenic fungi, including Alternaria alternata, Colletotrichum trichellum, Curvularia fallax, Cytospora sacchari, Fusarium oxysporum, and Macrophomina phaseolina was performed through disk diffusion and agar dilution assays. The essential oil of J. polycarpos var. turcomanica had high antifungal activity against tested phytopathogenic fungi. The most susceptible fungi to the essential oil were C. trichellum in agar dilution and M. phaseolina and C. fallax in disk diffusion methods, whereas, the most resistant fungus to the essential oil was obtained from A. alternata in both assays. Screening methods had an influence on antifungal activity of the essential oil as most of the tested fungi in this study were shown to be more resistant in disc diffusion methods. According to the phytotoxic assay results, the essential oil from J. polycarpos var. turcomanica had high phytotoxicity against three species of weeds, including P. oleracea L., A. retroflexus L., and D. stramonium L. The results of this research suggest that the herbicidal and antifungal activities of the essential oil from J. polycarpos var. turcomanica can be attributed to its major group of constituents, monoterpenes hydrocarbons.  相似文献   

2.
The genus Juniperus L. (Cupressaceae), an aromatic evergreen plant, consists of up to 68 species around the world. We classified five species of Juniperus found in Iran using molecular markers to provide a means for molecular identification of Iranian species. Plants were collected (three samples of each species) from two different provinces of Iran (Golestan and East Azarbayejan). The DNA was extracted from the leaves using a Qiagen Dneasy Plant Mini Kit. Amplification was performed using 18 ten-mer RAPD primers. Genetic distances were estimated based on 187 RAPD bands to construct a dendrogram by means of unweighted pair group method of arithmetic means. It was found that J. communis and J. oblonga were differentiated from the other species. Genetic distance values ranged from 0.19 (J. communis and J. oblonga) to 0.68 (J. communis and J. excelsa). Juniperus foetidissima was found to be most similar to J. sabina. Juniperus excelsa subspecies excelsa and J. excelsa subspecies polycarpos formed a distinct group.  相似文献   

3.
The distribution and status of the montane juniper woodlands of Oman   总被引:3,自引:0,他引:3  
Abstract. The distribution, condition and reproductive status of Juniperus excelsa M. -Bieb. subsp. polycarpos (K.Koch) Takhtajan were determined and assessed in the Hajar mountains of northern Oman, Arabia. Juniper is restricted to the highest areas, viz the central massif of Jebel Akhdar and the outlying mountains of Jebel Qubal and Jebel Kawr, where it generally forms open woodlands.
On exposed slopes juniper is distributed from an altitude of 2100 m to the highest summit at 3009 m, with no upper tree line, while on well-shaded north-facing slopes juniper trees grow as low as 1375 m. Above 2300 m, juniper is the dominant woody species, while below this altitude it is often co-dominant with Olea europea L. The woodlands are generally in poor condition on exposed slopes below 2400 m, with high proportions of dead or dying trees and low proportions of reproductively active trees. Above 2400 m and in shaded sites, woodland condition is better, with markedly higher proportions of reproductively active trees on exposed slopes at these altitudes. A predictive model of woodland condition based on topographic variables is presented. Altitude, shade and habitat account for 30.8% of the variation in a tree condition index, with slope being unimportant.
The absence of juniper from lower and more outlying mountains is likely to have resulted from the alternation of pluvial and arid periods over the last 40,000 years. We speculate that the current dieback of juniper at lower altitudes is due to continuing climatic change. Anthropogenic factors do not appear to be seriously affecting the juniper woodlands at present.  相似文献   

4.
Juniperus excelsa and J. thurifera are considered to originate from the same ancestor. As a result of occurring in geographically isolated refuges – J. excelsa in SE Europe and SW Asia and J. thurifera in SW Europe and NW Africa – their divergence could have taken place at the end of the Tertiary, with the climate cooling. Juniperus foetidissima occurs in SE Europe and SW Asia in territories shared with J. excelsa and is similar to and sometimes misidentified with it. The occurrence of the latter two species over the same area suggests they should be more similar to each other than to the geographically distant J. thurifera . Four populations of J. excelsa ssp. excelsa , four of J. thurifera and two of Juniperus foetidissima were examined on the basis of features of 10 cones and 10 shoots of 18–36 specimens each. Results of discrimination analysis, Mahalanobis distances and cluster analysis showed great similarity to J. excelsa and J. thurifera , while J. foetidissima was more distant. The results support the hypothesis of a common ancestor of J. excelsa and J. thurifera , but suggest another origin of J. foetidissima .  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 155 , 483–495.  相似文献   

5.
Juniperus communis has been used e.g. as poles (posts), haysticks and wall-coating. In some districts it has even been an important export article. The fields of columnar juniper are the result of a long history of cultivation and grazing. In this article the main types of juniper fields in Sogn, Western Norway are presented, and their relationships to soil conditions and traditional use are discussed. According to structure, utilization and development four main types of juniper fields are recognized: I. Traditional juniper fields, II. Semi-cultural juniper fields, III. Secondary juniper fields and IV. Semi-natural juniper fields. Due to changes in agricultural methods, juniper fields are becoming rare.  相似文献   

6.
Genetical control of nine enzyme systems has been studied in preserved juniper species (Juniperus excelsa Bieb.) of the natural population of the mountain Crimea. Isozymes were extracted from the haploid seed endosperms and separated elecrophoretically. As a result 16 loci have been identified. Fourteen of them were polymorphic (14--Gdh, Got-1, Mdh-1, Mdh-2, Mdh-3, Acp-1, Acp-2, Acp-3, Lap-1, Dia-1, Fdh, Sod-1, Sod-2, Sod-3). Analysis of the allele segragation of the heterozygous trees confirmed their monogenic inheritance.  相似文献   

7.

Key message

Intensity and magnitude of the growth-climate relationship depends on juniper species and sites. Juniperus seravschanica at low elevations shows highest potential for April–September drought reconstruction in the Turkestan range (Pamir-Alay), Uzbekistan.

Abstract

We present a detailed dendroclimatological study of three juniper species, Juniperus seravschanica Kom., Juniperus semiglobosa Regel and Juniperus turkistanica Kom., sampled at six sites of different elevation (2100–2700 m a.s.l.), exposition (west and south) and steepness (10°–30°) in the Zaamin National Park, Turkestan range, Pamir-Alay mountain system in eastern Uzbekistan. Simple correlation statistics and redundancy analyses were applied to detect species- and site-specific climate responses during the twentieth century, which were additionally investigated in the high-frequency domain by identifying extreme growth years. Our results show that tree-ring formation of J. seravschanica at our low-elevation site is strongly limited by April to September drought conditions, while J. semiglobosa inherits a weak and variable climate response with respect to elevation. J. turkistanica growth at high altitudes is positively associated with warm spring and summer temperatures. Species-specific growth extremes are triggered by incoming air masses from the Atlantic and Arctic, highlighting the connection of synoptic climate regimes across Eurasia. From a dendroclimatic perspective, J. seravschanica exhibits a high potential for reconstructing past drought and pluvials, but under sustained temperature rise also J. semiglobosa will likely increase its sensitivity to drought. Moreover, J. turkistanica at its distribution limit at the tree line is a suitable proxy of summer temperature. Our findings clearly demonstrate that a careful selection of the site, overall topography and elevation as well as the different juniper species are important for successfully reconstructing past climate in Uzbekistan.
  相似文献   

8.
Two eudesmanes, two abietanes, two podocarpanes and other nine known compounds were isolated from the dried fruits of Juniperus polycarpus var. seravschanica. Their structures were established on the basis of analysis of spectroscopic evidence. Some of the isolated terpenoids showed antimalarial activity.  相似文献   

9.
Background and AimsUnderstanding the population genetics and evolutionary history of endangered species is urgently needed in an era of accelerated biodiversity loss. This knowledge is most important for regions with high endemism that are ecologically vulnerable, such as the Qinghai–Tibet Plateau (QTP).MethodsThe genetic variation of 84 juniper trees from six populations of Juniperus microsperma and one population of Juniperus erectopatens, two narrow-endemic junipers from the QTP that are sister to each other, was surveyed using RNA-sequencing data. Coalescent-based analyses were used to test speciation, migration and demographic scenarios. Furthermore, positively selected and climate-associated genes were identified, and the genetic load was assessed for both species.Key ResultsAnalyses of 149 052 single nucleotide polymorphisms showed that the two species are well differentiated and monophyletic. They diverged around the late Pliocene, but interspecific gene flow continued until the Last Glacial Maximum. Demographic reconstruction by Stairway Plot detected two severe bottlenecks for J. microsperma but only one for J. erectopatens. The identified positively selected genes and climate-associated genes revealed habitat adaptation of the two species. Furthermore, although J. microsperma had a much wider geographical distribution than J. erectopatens, the former possesses lower genetic diversity and a higher genetic load than the latter.ConclusionsThis study sheds light on the evolution of two endemic juniper species from the QTP and their responses to Quaternary climate fluctuations. Our findings emphasize the importance of speciation and demographic history reconstructions in understanding the current distribution pattern and genetic diversity of threatened species in mountainous regions.  相似文献   

10.
Semi‐natural grasslands, among them thin‐soil calcareous grasslands (alvars), have great conservation value but have become increasingly rare in Europe. The main threat to alvar grasslands is the encroachment by juniper Juniperus communis and therefore it is usually removed during the restoration practice. Juniper can also be a host plant for many epiphytic lichens, but its role as a phorophyte is poorly known. We studied epiphytic lichen diversity on 126 junipers in 17 sites in western Estonia and found 140 lichenized taxa including several rare and red‐listed species. Using indirect and direct multivariate analyses (DCA, pCCA) and general linear models we revealed that both habitat and phorophyte properties affect lichen assemblies on juniper. Lichen species richness per site showed a unimodal relationship with compound factors of site productivity and juniper characteristics (stem circumference and juniper width). Lichen species richness per phorophyte was increasing with its size and with the proportion of dead branches, and was twice higher in plate alvars than in ryhk alvars. Also, the species composition in plate alvars differed from ryhk alvars by having 42 characteristic lichen species in plate alvars vs three indicators of ryhk alvars. The composition of lichens was significantly influenced by encroachment of alvars, e.g. by high juniper cover and shrub layer height, as well as by the proportion of dead branches and stem circumference of juniper. We conclude that the epiphytic lichen assemblies on junipers are threatened by grassland encroachment similarly to ground layer lichen assemblies. We suggest that some old and scencent junipers should be preserved during the restoration of alvar grasslands.  相似文献   

11.
控制西美圆柏数量对美国俄勒冈州中部生态系统氮储量的影响 在美国俄勒冈州,控制西美圆柏(Juniperus occidentalis)的数量是一种公认的牧场管理措施,该做法 有助于恢复蒿草草原(sagebrush steppe)生境,该生境对野生动物和家畜都十分重要。然而,尽管控制木本 植物数量会对当地的流域管理和区域性氮库造成重要影响,但砍伐西美圆柏对生态系统中氮元素的影响问题尚未得到很好的解决。本文定量研究了两个相邻流域生态系统中的氮储量,其中一个流域经过处理(流域内的大部分圆柏已被清除掉),而另一个流域未处理(圆柏未被清除)。在圆柏被移除13年后,我们测定了两个流域里圆柏树林、灌木丛、草丛和枯枝落叶层的地上氮储量,以及两个流域中两个土层(0–25和25–50 cm)内的地下氮储量(根系和土壤氮储量)。研究结果表明,未处理流域的地上氮储量是处理流域 的6.9倍,因为未处理流域的地上生物量要大得多。然而,由于砍伐圆柏导致林下植被的根系生物量增加,所以处理流域的根系氮储量是未处理流域的3.1倍。0–25和25–50 cm土层氮储量没有受到圆柏砍伐的影响。总体而言,生态系统总氮储量在处理流域(9536 kg N ha−1)和未处理流域(9456 kg N ha−1)之间并没有显著差异。在两个流域里,生态系统中最大的氮积累量(至少95%的生态系统总氮量)均存在于地下(0–25 cm深的土壤以及根系)。这项研究证明,清除圆柏并不会显著影响生态系统的储氮能力。  相似文献   

12.
Piñon–juniper (Pinus spp.–Juniperus spp.) woodlands are common throughout western North America, yet relatively little is known about the habitat use and requirements for many members of its avian community. During summer 2005–2007, we assessed avian nesting substrates within piñon (Pinus edulis)–juniper (Juniperus osteosperma) woodlands in northwestern New Mexico. Of all nests in live trees, 86% were in junipers. The selection of juniper as a nest tree was significantly higher than expected from the region's piñon–juniper ratio (1:1.06) for the community as a whole, for both open cup and cavity nesting species, and for 8 species (of which 6 are piñon–juniper obligate or semi-obligate species). Nest survival, however, was not higher in juniper than in piñon for the nesting community as a whole or for chipping sparrows (Spizella passerina), the single species that was well represented nesting in piñon. The high use of juniper as a nesting substrate differs from previous studies, which have suggested that a presence of piñon is among the most important habitat features for many piñon–juniper species. Because of their importance to nesting birds, managers should avoid preferential thinning of junipers within piñon–juniper woodlands. © 2011 The Wildlife Society.  相似文献   

13.
Analysis of the spatial patterns of woody plants is important to better understand the ecological processes that govern the worldwide expansion of woody plants across semi-arid ecosystems. Second-order characteristics of a marked spatial point pattern of western juniper (Juniperus occidentalis subsp. occidentalis) were analyzed using Ripley’s K-functions and the pair-correlation function g. The marked point process of crown diameters was produced via two-dimensional wavelet analysis of a fine scale aerial photograph at the woodland-steppe ecotone in the Reynolds Creek watershed in the Owyhee Mountains, southwestern Idaho. Colonization of J. occidentalis stems from mature juniper trees growing in rocky, fire resistant areas. Although these areas introduce components of natural heterogeneity within the landscape, the selected study area is situated within a single soil type, and we modeled the expansion of juniper plants into previously juniper-free sagebrush steppe as a homogeneous point process with constant intensity. Through this research we have identified two statistically significant spatial scales characteristic of J. occidentalis on the woodland/steppe ecotone: (1) We observed inhibition between J. occidentalis plants at distances <15 m, resulting in a regular pattern, rather than clumped or random. This short-distance inhibition can be attributed to competition for water and other resources. Recruitment of young J. occidentalis occurs significantly more often in a direction away from older plants, maximizing the utilization of water and light resources, and perpetuating the spread of the species into previously juniper-free shrub-steppe. (2) J. occidentalis on the ecotone exhibits significant clustering within a 30–60 m radius. Bivariate point pattern analyses provide evidence that, within a distance of 50–70 m, there is a spatial dependence in tree size such that medium trees are more likely than small trees to be close to large trees. We attribute these phenomena to the fact that juniper seeds are commonly dispersed by berry-eating birds with small territories (0.3–1 ha). Beyond a distance of 50–70 m, juniper plants are randomly distributed, suggesting that additional long-range seed dispersal processes are at work. We further acknowledge the importance of including a reference to spatial scale when formulating hypotheses in statistical analysis of spatio-temporal point patterns.  相似文献   

14.
Ingestion of plant secondary compounds by herbivores is predicted to increase resting or basal metabolic rates. We tested this hypothesis with two species of woodrat herbivores, Neotoma stephensi and Neotoma albigula, consuming diets of juniper (Juniperus monosperma), which is rich in plant secondary compounds. In nature, N. stephensi specializes on juniper, whereas N. albigula consumes a variety of plant species including juniper. We measured resting metabolic rates (RMR) of woodrats on control, 25% juniper and a treatment containing the maximum tolerable dose of juniper (50% juniper for N. albigula and 70% juniper for N. stephensi). Ingestion of a juniper diet resulted in decreased RMR in both species of woodrats. We propose several potential mechanisms for metabolic depression of Neotoma on juniper diets. Our novel results underscore the need for more studies utilizing plant-based diets to determine the general effect of plant secondary compounds on metabolic rates of herbivores.  相似文献   

15.
The population structure of common juniper (Juniperus communis L.) growing in the Cis-Urals and Southern Urals has been studied using 17 morphological traits of generative and vegetative organs. A multivariate analysis of ten coenopopulations has recognized three phenotypically different local populations: Cis-Ural, forest Cis-Ural forest-steppe, and Southern Ural mountain populations. The Cis-Ural forest population is strictly associated with lowland pine forests of the northwestern part of the Bashkir Cis-Urals. The Cis-Ural forest-steppe population is located in the northwestern part of the Bashkir Cis-Urals and the southeastern part of the Udmurt Cis-Urals. The Southern Ural mountain population is located in the central part of the Southern Urals and is associated mainly with mountain pine and dark coniferous forests. The last population is divided into forest and forest-edge subpopulations; the first one is represented by typical undergrowth locations, whereas the second is associated with open steppelike slopes and forest edges. In general, based on morphological traits of generative organs, the revealed local subpopulations hold an intermediate position between the Eastern European and Siberian populations of common juniper. Based on the morphological traits of vegetative organs, Cis-Ural populations are considered related to the populations of the European part of Russia, whereas the mountain Southern Ural population resemble Siberian populations. Concerning morphological traits of generative organs, the intrapopulation phenotypic diversity of common juniper is higher for mountain habitats; in the case of vegetative organs, the maximum diversity is observed for lowland habitats. The character of phenotypic differentiation determines the need to conserve the gene pool of common juniper of the Cis-Urals and southern Urals on a population basis.  相似文献   

16.
In Vitro Cellular & Developmental Biology - Plant - Foetid juniper (Juniperus foetidissima Willd.) is one of the most important coniferous species faced with multiple threats and it is...  相似文献   

17.
The pollination droplet is a highly conservative pollination mechanism that is observed in all major gymnosperm taxa. Proteomics analysis of the pollination drops was carried out on four gymnosperm species: Juniperus communis (common juniper), Juniperus oxycedrus (prickly juniper), Chamaecyparis lawsoniana (Port Orford cedar), and Welwitschia mirabilis. Pollination drop proteins were purified by SDS-PAGE, and the most abundant proteins were analyzed by mass spectrometry and sequenced. Based on BLAST searching of combined amino acid sequences, the following proteins were identified in the following species: an 83-kDa subtilisin-like proteinase, a 62-kDa glycosyl hydrolase, a 47.5-kDa glucan 1,3-β-glucosidase precursor, a 30-kDa chitinase, and a 25-kDa thaumatin-like protein were identified in J. communis; a 30-kDa chitinase, a 25-kDa thaumatin-like protein, and a 32.5-kDa glucanase-like protein were identified in J. oxycedrus; an 83-kDa subtilisin-like proteinase, a 62-kDa β-d-glucan exohydrolase, a 47.5-kDa glucan 1,3-β-glucosidase, and two 25-kDa thaumatin-like proteins were identified in C. lawsoniana, and a 25-kDa chitinase was identified in W. mirabilis. Based on protein identifications, there is strong evidence that the pollination drop functions in both pathogen defense and pollen development. The discovery of similarities in terms of peptide sequence and protein identifications indicates that ovular secretions are functionally conservative, and that they are essential to reproductive success.  相似文献   

18.
Juniperus phoenicea L. is listed as threatened tree by IUCN Red List. In Egypt, J. phoenicea L. is the only conifer tree that is restricted to the three mountains of northern Sinai: Gabal El-Halal, Gabal El-Maghara and Gabal Yelleq. As a Mediterranean relict it has been included in a national list as target for conservation and management. To provide baseline information for the development of a conservation strategy, the present study aims at comparing the isolated populations of J. phoenicea and their associated plant composition and diversity at the three mountains. The application of TWINSPAN and DCA analysis techniques has resulted in identifying of four vegetation types associated with juniper, and each could be related to a specific geomorphologic habitat on a topographic gradient. Chiliadenus montanus and Zygophyllum dumosum characterized the slopes of smooth-faced rock outcrops in Wadi Abu Seyal (at 350–470 m altitude of Gabal El-Halal), Deverra tortuosa, Ephedra aphylla and Gymnocarpos decander inhabited together with the target species the soil pockets of north-facing slope in Neqeb Abu Hamam (at 600–700 m altitude of Gabal El-Halal), Stachys aegyptiaca and Moricandia nitens characterized the juniper occurrences in the runnels of Wadi Arar (at 450–560 m altitude of Gabal El-Maghara), and Artemisia herba-alba, Atriplex halimus and Reaumuria hirtella represent the stands on slope runnels (at 900–960 m) of Gabal Yelleq. The two vegetation types recognized at Gabal El-Halal had, on average, the highest species diversity, juniper density and cover. Juniper shows generally poor conditions of vitality at higher elevation (600–960 m) with a higher proportions of old and recent dead trees, and with the predominance of male individuals, as compared with the populations of Gabal El-Maghara and Gabal Yelleq. In contrast, the juniper populations at lower elevation (350–470 m) of Gabal El-Halal proved to be in best condition with mostly living foliage and reproductive branches. The differences in rock types and elevation among the three mountains reflect serious limitation on recruitment of J. phoenicea due to moisture availability. The results of this study showed that J. phoenicea is an endangered species and its conservation in northern Sinai mountains is a priority. For a successful conservation of this community it is highly recommended to preserve in particular the suitable habitats at Gabal El-Halal, but also the other stands merit conservation measures.  相似文献   

19.
The whitethroat woodrat (Neotoma albigula) eats juniper (Juniperus monosperma), but the amount of juniper in its diet varies seasonally. We tested whether changes in juniper consumption are due to changes in ambient temperature and what the physiological consequences of consuming plant secondary compounds (PSCs) at different ambient temperatures might be. Woodrats were acclimated to either 20 degrees C or 28 degrees C. Later, they were given two diets to choose from (50% juniper and a nontoxic control) for 7 d. Food intake, resting metabolic rate (RMR), and body temperature (T(b)) were measured over the last 2 d. Woodrats at 28 degrees C ate significantly less juniper, both proportionally and absolutely, than woodrats at 20 degrees C. RMRs were higher for woodrats consuming juniper regardless of ambient temperature, and T(b) was higher for woodrats consuming juniper at 28 degrees C than for woodrats eating control diet at 28 degrees C. Thus, juniper consumption by N. albigula is influenced by ambient temperature. We conclude that juniper may influence thermoregulation in N. albigula in ways that are helpful at low temperatures but harmful at warmer temperatures in that juniper PSCs may be more toxic at warmer temperatures. The results suggest that increases in ambient temperature associated with climate change could significantly influence foraging behavior of mammalian herbivores.  相似文献   

20.
《Journal of bryology》2013,35(1):23-31
Abstract

The forests of Juniperus thurifera are peculiar ecosystems that typically grow on mountains and highplateaux of the western Mediterranean basin with dry and continental climates. Some previous surveys suggested that these forests house a rather distinctive epiphytic bryophyte flora. Epiphytic bryophyte communities were systematically sampled in 19 representative juniper forests, for the first time spanning all the distribution area of this conifer. The flora consists of 44 species (32 acrocarpous mosses, 10 pleurocarpous mosses and 2 liverworts). Orthotrichum species are the most frequent and abundant in most of the sampled localities, including some uncommon taxa such as Orthotrichum vittii which shows a clear association with J. thurifera. Epiphytic bryophyte communities on this species were highly homogeneous, although they can be arranged into different groups in response to environmental conditions. Typically, the epiphytic communities of the Mediterranean juniper forests comprise a distinct combination of xerophytic taxa that enhances the interest of these ecosystems and provides new fields for their research and conservation.  相似文献   

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