| air-pollutant dispersal patterns and vegetation damage in the vicinity of three aluminium smelters in norway. | dispersal patterns for fluoride and damage to vegetation was studied near three aluminium smelters in norway. leaf samples from three broad-leaved species (betula pubescens ehrh., salix caprea l. and sorbus aucuparia l.) were collected and leaf injury and the plants overall vitality were evaluated systematically in areas with different distance and direction from the emission sources. both dispersal patterns and the distribution of damages were mainly determined by the predominant wind direction ... | 1999 | 10535145 |
| chloroplast dna haplotype variation and population differentiation in sorbus aucuparia l. (rosaceae: maloideae). | intra-specific chloroplast dna (cpdna) variation was studied in sorbus aucuparia l., an entomophilous, mid-or early successional tree producing fleshy fruits. eight pcr-amplified fragments of the chloroplast genome were screened for restriction fragment length polymorphisms, using one or two 4 bp-cutter restriction endonucleases. cpdna variation was investigated on two geographical scales: (1) among four regions in france and belgium; and (2) within the belgian region. a total of 150 individuals ... | 2000 | 10964230 |
| phenological modifications in plants by various edaphic factors. | various mechanical, chemical and physical soil analyses were carried out, in addition to weather observations, for 3 years at several sites along an oceanic-continental gradient in a fjord district in western norway. all the environmental factors observed were correlated with the spring and a few late-season phenophases of many native and cultivated woody plants and some herbs by simple, linear correlations and by stepwise multiple and partial analyses. different techniques were used to try and ... | 2001 | 11769320 |
| host-associated allozyme variation in tree cambium miners, phytobia spp. (diptera: agromyzidae). | the larvae of the agromyzid flies that belong to the genus phytobia lioy feed by mining in the differentiating xylem just below the cambium of growing forest trees. the genus, which is apparently one of the most primitive groups in the agromyzidae, comprises over 50 currently recognized species. most of the species are mono- or oligophagous, and the host plants belong to numerous genera in about 60 families. thus, phytobia is an attractive candidate for studies on the evolution of insect-plant r ... | 2002 | 12399999 |
| biphenyl synthase from yeast-extract-treated cell cultures of sorbus aucuparia. | biphenyls and dibenzofurans are the phytoalexins of the maloideae, a subfamily of the economically important rosaceae. the biphenyl aucuparin accumulated in sorbus aucuparia l. cell cultures in response to yeast extract treatment. incubation of cell-free extracts from challenged cell cultures with benzoyl-coa and malonyl-coa led to the formation of 3,5-dihydroxybiphenyl. this reaction was catalysed by a novel polyketide synthase, which will be named biphenyl synthase. the most efficient starter ... | 2004 | 14595561 |
| bioindicator plants for ambient ozone in central and eastern europe. | sixteen species of native detector plants for ambient ozone have been identified for use in central and eastern europe. they include the forbs alchemilla sp., astrantia major, centuarea nigra, centauria scabiosa, impatiens parviflora, lapsana communis, rumex acetosa and senecio subalpinus; the shrubs corylus avellana, cornus sanguinea and sambucus racemosa; the trees alnus incana, pinus cembra and sorbus aucuparia; and the vines humulus lupulus and parthenocissus quinquefolia. sensitivity to ozo ... | 2004 | 15046838 |
| avoidance of nonhost plants by a bark beetle, pityogenes bidentatus, in a forest of odors. | the bark beetle, pityogenes bidentatus (coleoptera: scolytidae), searches in mixed conifer and deciduous forests of northern europe for suitable branches of its host, scots pine ( pinus sylvestris). we tested whether odors from several diverse nonhost trees and plants common in the habitat (e.g., mountain ash, sorbus aucuparia; oak, quercus robur; alder buckthorn, frangula alnus; blueberry, vaccinium myrtillus; raspberry, rubus idaeus; and grass, deschampsia flexuosa) would reduce the attraction ... | 2004 | 15146267 |
| allergic contact dermatitis from salicyl alcohol and salicylaldehyde in aspen bark (populus tremula). | salicyl alcohol or 2-methylolphenol is a well-known allergen in phenol-formaldehyde resins and a strong sensitizer in guinea pigs. there is 1 previous report of allergic contact dermatitis from salicyl alcohol in aspen bark. we describe a second case with concomitant allergy to salicylaldehyde. an elk researcher who had handled leaves from various trees presented with eczema of the hands, face, flexures, trunk and extremities. patch testing showed sensitivity to salicyl alcohol, salicylaldehyde, ... | 2005 | 15725287 |
| new, rare or remarkable microfungi in the italian alps (carnic alps)--part i--ascomycotina. | during our observations in the se part of the carnic alps in the year 2003 we were able to collect and identify 35 ascomycetes on trees and dead wood. among these one can find numerous ascomycetes of different orders e.g. pyrenomycetes, loculoascomycetes and discomycetes. some species like botryosphaeria ribis grosenlucher & duggar on ribes alpinum l., dothiora pyrenophora (fr.) fr. on sorbus aucuparia l., gemmamyces piceae (borth.) casago. on picea excelsa (lam.) link, glomerella montana (sacc. ... | 2004 | 15756826 |
| purification and characteristics of sorbitol-6-phosphate dehydrogenase from loquat leaves. | to study the role of sorbitol-6-phosphate dehydrogenase in sorbitol synthesis in leaves of rosaceous plants, properties of the enzyme and its presence in several plants in the family was investigated. the activity of the enzyme, which catalyzes an nadp-dependent oxidation of the substrate to glucose-6-phosphate, was detected in leaves of prunus mume, prunus persica, rhaphiolepsis indica, sorbus aucuparia, cydonia oblonga, photinia glabra, sorbaria kirilowii, and spiraea thunbergii.the enzyme was ... | 1981 | 16661650 |
| invasion through quantitative effects: intense shade drives native decline and invasive success. | the effects of invasive nonnative species on community composition are well documented. however, few studies have determined the mechanisms by which invaders drive these changes. the literature indicates that many nonnative plant species alter light availability differently than natives in a given community, suggesting that shading may be such a mechanism. we compared light quantity (photosynthetically active radiation, par) and quality (red: far-red ratio, r:fr) in riparian reaches heavily inva ... | 2006 | 17069374 |
| biphenyl synthase, a novel type iii polyketide synthase. | biphenyls and dibenzofurans are the phytoalexins of the maloideae, a subfamily of the economically important rosaceae. the carbon skeleton of the two classes of antimicrobial secondary metabolites is formed by biphenyl synthase (bis). a cdna encoding this key enzyme was cloned from yeast-extract-treated cell cultures of sorbus aucuparia. bis is a novel type iii polyketide synthase (pks) that shares about 60% amino acid sequence identity with other members of the enzyme superfamily. its preferred ... | 2007 | 17109150 |
| notes on a plant parasite fungus in portugal: gymnosporangium cornutum. | a rust fungus identified as gymnosporangium cornutum was found on sorbus aucuparia in serra da estrela (manteigas), and the disease was severe at that location. despite the abundance and worldwide occurrence of the genus gymnosporangium, studies in portugal are still limited. | 2006 | 17196029 |
| a novel, multipartite, negative-strand rna virus is associated with the ringspot disease of european mountain ash (sorbus aucuparia l.). | four rnas from a new plant-pathogenic virus, which we have tentatively named european mountain ash ringspot-associated virus (emarav), were identified and sequenced completely. all four viral rnas could be detected in previous double-stranded rna preparations. rna 1 (7040 nt) encodes a protein with similarity to the rna-dependent rna polymerase of different members of the bunyaviridae, a family containing five genera with viruses infecting invertebrates, vertebrates and plants. rna 2 (2335 nt) e ... | 2007 | 17374780 |
| element contents in leaves of four plant species (birch, mountain ash, fern and spruce) along anthropogenic and geogenic concentration gradients. | forty samples each of leaves of birch (betula pubescens ehrh.), european mountain ash (sorbus aucuparia (l.)) and bracken fern (pteridium aquilinum (l.) kuhn) as well as spruce needles (picea abies (l.) karsten) were collected along a 120 km south-north transect running through norway's largest city, oslo. concentrations of 25 chemical elements (ag, au, b, ba, ca, cd, co, cr, cu, fe, hg, k, la, mg, mn, mo, na, ni, p, pb, s, sb, sr, ti, and zn) as well as loss on ignition for the 4 sample materia ... | 2007 | 17379275 |
| population structure at the s-locus of sorbus aucuparia l. (rosaceae: maloideae). | low sequence divergence within functional alleles is predicted for the self-incompatibility locus because of strong negative frequency-dependent selection. nevertheless, sequence variation within functional alleles is essential for current models of the evolution of new mating types. we genotyped the stylar self-incompatibility rnase of 20 sorbus aucuparia from a population in the pyrenees mountains of france in order to compare alleles found there to those previously sampled in a belgian popula ... | 2007 | 17391416 |
| diversity of predominant endophytic bacteria in european deciduous and coniferous trees. | the diversity of endophytic bacteria residing in root, stem, and leaf tissues was examined in coniferous and deciduous tree species, scots pine (pinus sylvestris l.), silver birch (betula pendula roth), and rowan (sorbus aucuparia l.). using cultivation-dependent and -independent analyses, the bacterial communities were observed to be significantly different in the belowground (roots and rhizosphere) and aboveground (leaves and stems) samples of the respective host trees. no significant differen ... | 2008 | 18388988 |
| a comparison of phenological models of leaf bud burst and flowering of boreal trees using independent observations. | we compared and tested thermal time, sequential, parallel and flexible phenological models of leaf bud burst in birch (betula pendula roth. and b. pubescens ehrh.) and flowering in bird cherry (prunus padus l.) and rowan (sorbus aucuparia l.). we used phenological records from oulainen-ohineva (64 degrees 13' n, 24 degrees 53' e) in central finland from 1953 to 2002 to estimate model parameters. we tested the models with data collected in all but six years between 1896 and 2002 in southern and c ... | 2008 | 19193570 |
| a multipartite single-stranded negative-sense rna virus is the putative agent of fig mosaic disease. | several dsrna bands (approx. 0.6-7 kbp in size) were recovered from tissues of mosaic-diseased fig seedlings which contained the enveloped round structures known as double membrane bodies (dmbs). blast analysis of a 4353 and a 1120 nt sequence from the two largest rna segments showed homology with the polymerase and the putative glycoprotein precursor genes of negative-sense single-stranded rna viruses of the family bunyaviridae. negative- and positive-sense riboprobes designed from both rna seg ... | 2009 | 19264612 |
| detection, distribution, and genetic variability of european mountain ash ringspot-associated virus. | european mountain ash ringspot-associated virus (emarav) was recently characterized from mountain ash (rowan) (sorbus aucuparia) in germany. the virus belongs tentatively to family bunyaviridae but is not closely related to any classified virus. how commonly emarav occurs in ringspot disease (emarsd) affected mountain ash trees was not reported and was investigated here. virus-specific detection tools such as reverse transcription-polymerase chain reaction and dot blot hybridization using digoxi ... | 2009 | 19271975 |
| complete nucleotide sequence of four rna segments of fig mosaic virus. | the complete sequence of four viral rna segments of fig mosaic virus (fmv) was determined. each of the four rnas comprises a single open reading frame (orf) 7,093, 2,252, 1,490 and 1,472 nucleotides in size, respectively. these orfs encode the following proteins in the order: rna-dependent rna polymerase (p1 264 kda), a putative glycoprotein (p2 73 kda), a putative nucleocapsid protein (p3 35 kda) and a protein with unknown function (p4 40.5 kda). all rna segments possess untranslated regions co ... | 2009 | 19777155 |
| [spacial structure of epiphytic yeast communities on fruits of sorbus aucuparia l]. | the subject of this research is epiphytic yeast communities that form on the surface of sorbus aucuparia. the object is to make quantitative assessment of the yeast communities' differentiation of the same but distant substratum. results of the factor variance nidicolous analysis demonstrated that with increase in distances, there are increases in the variation of total number and relative abundance of the dominant yeast communities. the average similarity between groups of single fruits (sorens ... | 2009 | 20143631 |
| detection of european mountain ash ringspot-associated virus-specific rna and protein p3 in the pear leaf blister mite phytoptus pyri (eriophyidae). | the means by which european mountain ash ringspot-associated virus (emarav), a minus-strand ssrna virus and the type member of the genus emaravirus, is naturally spread, is unknown. in attempts to identify an emarav vector, galls induced by the eriophyid mite phytoptus pyri were frequently found on infected leaves. by immunofluorescence microscopy, the presence of emarav nucleocapsid protein p3 was demonstrated in p. pyri individuals collected from diseased plants. furthermore, rt-pcr analysis o ... | 2010 | 20401694 |
| forage quantity, quality and depletion as scale-dependent mechanisms driving habitat selection of a large browsing herbivore. | 1. mechanisms that affect the spatial distribution of animals are typically scale-dependent and may involve forage distribution. forage quality and quantity are often inversely correlated and a much discussed trade-off is whether or not to select for high-quality forage at the expense of forage abundance. this discussion has rarely involved scale-dependence or been applied to northern browsing herbivores. at small spatial scales, browsers are assumed to select for the best quality forage. but, a ... | 2010 | 20443990 |
| characterization of selected wild mediterranean fruits and comparative efficacy as inhibitors of oxidative reactions in emulsified raw pork burger patties. | in the present study, water, ethanolic, and methanolic extracts from seven selected wild fruits originally from the mediterranean area, namely, strawberry tree ( arbutus unedo l., au), azarole ( crataegus azarolus l., ca), common hawthorn ( crataegus monogyna l., cm), blackthorn ( prunus spinosa l., ps), dog rose ( rosa canina l., rc), elm-leaf blackberry ( rubus ulmifolius schott, ru), and rowan ( sorbus aucuparia l., sa), were analyzed for the total amount and profile of phenolic compounds and ... | 2010 | 20681673 |
| differential effect of elicitors on biphenyl and dibenzofuran formation in sorbus aucuparia cell cultures. | the rosaceous subtribe pyrinae (formerly subfamily maloideae) is well-known for its economically important fruit trees, such as apple and pear, and also includes sorbus aucuparia. elicitor-treated s. aucuparia cell cultures are used to study the biosynthesis of the pyrinae-specific phytoalexins, biphenyls and dibenzofurans. three biphenyls (aucuparin, noraucuparin, 2'-hydroxyaucuparin) and a dibenzofuran (eriobofuran) were isolated and structure elucidated using gc-ms and nmr. a second dibenzofu ... | 2010 | 20961041 |
| rowanberry phenolics: compositional analysis and bioactivities. | berries contain a large variety of different phenolic compounds such as anthocyanins, flavonols, tannins, and phenolic acids. due to variation in the nature and content of the phenolic compounds, the antioxidant effect and other bioactivities of berry phenolics are strongly dependent on the berry raw material as the activities differ between the different phenolic constituents. in the present study, wild rowanberries ( sorbus aucuparia ) and four cultivated sweet rowanberries, burka, granatnaja, ... | 2010 | 21038891 |
| 4-coumarate:coa ligase family members from elicitor-treated sorbus aucuparia cell cultures. | sorbus aucuparia cell cultures accumulate biphenyl and dibenzofuran phytoalexins in response to elicitor treatment. these polyketide derivatives arise from the starter substrate benzoyl-coa, the biosynthesis of which is largely unresolved. two coa ligases involved are cinnamate:coa ligase and benzoate:coa ligase, which were assumed to be related in s. aucuparia to the ubiquitous 4-coumarate:coa ligase (4cl). cdnas encoding three distinct 4cls from elicitor-treated s. aucuparia cell cultures were ... | 2011 | 21330005 |
| [comparative evaluation of 238u and 226ra absorption by herbaceous and woody species under man-made pollution]. | the results of studies on uranium and radium distribution in soil and vegetation at the territory contaminated by wastes of radium plant in 1930-1950 are presented. specific activities of 226ra and 238u in soil varied as 0.01-200 and 0.004-7.58 bq/g per ash respectively. the radionuclides are mainly concentrated in the upper layer of soil profile. in the vegetation concentrations of 226ra and 238u varied as 0.64-132 0.001-0.02 bq/g per ash respectively. among the woody species studied, betula pu ... | 2010 | 21434390 |
| surface tension phenomena in the xylem sap of three diffuse porous temperate tree species. | in plant physiology models involving bubble nucleation, expansion or elimination, it is typically assumed that the surface tension of xylem sap is equal to that of pure water, though this has never been tested. in this study we collected xylem sap from branches of the tree species populus tremuloides, betula papyrifera and sorbus aucuparia over 3 months. we measured the instantaneous surface tension and followed changes over a period of 0.5-5 h using the pendant drop technique. in all thr ... | 2011 | 21470981 |
| Differential Expression of Biphenyl Synthase Gene Family Members in Fire Blight-Infected Apple cv. 'Holsteiner Cox' | Fire blight, caused by the bacterium Erwinia amylovora, is a devastating disease of apple (Malus × domestica). The phytoalexins of apple are biphenyls and dibenzofurans, whose carbon skeleton is formed by biphenyl synthase (BIS), a type III polyketide synthase. In the recently published genome sequence of the apple variety 'Golden Delicious', nine BIS genes and four BIS gene fragments were detected. The nine genes fall into four subfamilies, referred to as MdBIS1 to MdBIS4. In a phylogenetic tre ... | 2011 | 22158676 |
| unrestricted quality of seeds in european broad-leaved tree species growing at the cold boundary of their distribution. | background and aimsthe low-temperature range limit of tree species may be determined by their ability to produce and disperse viable seeds. biological processes such as flowering, pollen transfer, pollen tube growth, fertilization, embryogenesis and seed maturation are expected to be affected by cold temperatures. the aim of this study was to assess the quality of seeds of nine broad-leaved tree species close to their elevational limit.methodswe studied nine, mostly widely distributed, european ... | 2011 | 22156401 |
| tree and shrub expansion over the past 34 years at the tree-line near abisko, sweden. | shrubs and trees are expected to expand in the sub-arctic due to global warming. our study was conducted in abisko, sub-arctic sweden. we recorded the change in coverage of shrub and tree species over a 32- to 34-year period, in three 50 x 50 m plots; in the alpine-tree-line ecotone. the cover of shrubs and trees (<3.5 cm diameter at breast height) were estimated during 2009-2010 and compared with historical documentation from 1976 to 1977. similarly, all tree stems (> or =3.5 cm) were noted and ... | 2011 | 21954730 |
| Endogenous hydrogen peroxide is a key factor in the yeast extract-induced activation of biphenyl biosynthesis in cell cultures of Sorbus aucuparia. | Biphenyls are unique phytoalexins produced by plants belonging to Pyrinae, a subtribe of the economically important Rosaceae family. The formation of aucuparin, a well-known biphenyl, is induced by yeast extract (YE) in cell cultures of Sorbus aucuparia. However, the molecular mechanism underlying YE-induced activation of biphenyl biosynthesis remains unknown. Here we demonstrate that the addition of YE to the cell cultures results in a burst of reactive oxygen species (ROS; H(2)O(2) and O(2) ... | 2012 | 22086110 |
| biphenyl 4-hydroxylases involved in aucuparin biosynthesis in rowan and apple are cytochrome p450 736a proteins. | upon pathogen attack, fruit trees such as apple (malus spp.) and pear (pyrus spp.) accumulate biphenyl and dibenzofuran phytoalexins, with aucuparin as a major biphenyl compound. 4-hydroxylation of the biphenyl scaffold, formed by biphenyl synthase (bis), is catalyzed by a cytochrome p450 (cyp). the biphenyl 4-hydroxylase (b4h) coding sequence of rowan (sorbus aucuparia) was isolated and functionally expressed in yeast (saccharomyces cerevisiae). sab4h was named cyp736a107. no catalytic function ... | 2015 | 25862456 |
| phytoalexins of the pyrinae: biphenyls and dibenzofurans. | biphenyls and dibenzofurans are the phytoalexins of the pyrinae, a subtribe of the plant family rosaceae. the pyrinae correspond to the long-recognized maloideae. economically valuable species of the pyrinae are apples and pears. biphenyls and dibenzofurans are formed de novo in response to infection by bacterial and fungal pathogens. the inducible defense compounds were also produced in cell suspension cultures after treatment with biotic and abiotic elicitors. the antimicrobial activity of the ... | 2012 | 22563359 |
| first evidence of established populations of the taiga tick ixodes persulcatus (acari: ixodidae) in sweden. | the tick species ixodes ricinus and i. persulcatus are of exceptional medical importance in the western and eastern parts, respectively, of the palaearctic region. in russia and finland the range of i. persulcatus has recently increased. in finland the first records of i. persulcatus are from 2004. the apparent expansion of its range in finland prompted us to investigate if i. persulcatus also occurs in sweden. | 2016 | 27370406 |
| control of plant defense mechanisms and fire blight pathogenesis through the regulation of 6-thioguanine biosynthesis in erwinia amylovora. | fire blight is a devastating disease of rosaceae plants, such as apple and pear trees. it is characterized by necrosis of plant tissue, caused by the phytopathogenic bacterium erwinia amylovora. the plant pathogen produces the well-known antimetabolite 6-thioguanine (6tg), which plays a key role in fire blight pathogenesis. here we report that ycfr, a member of the lttr family, is a major regulator of 6tg biosynthesis in e. amylovora. inactivation of the regulator gene (ycfr) led to dramatically ... | 2014 | 24449489 |
| emaravirus-specific degenerate pcr primers allowed the identification of partial rna-dependent rna polymerase sequences of maize red stripe virus and pigeonpea sterility mosaic virus. | emaravirus is a recently established viral genus that includes two approved virus species: european mountain ash ringspot-associated virus (emarav) and fig mosaic virus (fmv). other described but unclassified viruses appear to share biological characteristics similar to emaraviruses, including segmented, negative-single stranded rna genomes with enveloped virions approximately 80-200nm in diameter. sequence analysis of emaravirus genomes revealed the presence of conserved amino acid sequences in ... | 2013 | 23219928 |
| emaravirus: a novel genus of multipartite, negative strand rna plant viruses. | ringspot symptoms in european mountain ash (sorbus aucuparia l.), fig mosaic, rose rosette, raspberry leaf blotch, pigeonpea sterility mosaic (cajanus cajan) and high plains disease of maize and wheat were found to be associated with viruses that share several characteristics. they all have single-stranded multipartite rna genomes of negative orientation. in some cases, double membrane-bound virus-like particles of 80 to 200 nm in diameter were found in infected tissue. furthermore, at least fiv ... | 2012 | 23170170 |
| [effects of different types of elicitors on secondary metabolism of sorbus aucuparia cell cultures]. | to investigate the effects of different types of elicitors on the secondary metabolism of sorbus aucuparia cell). | 2014 | 25508579 |
| [effects of different types of elicitors on secondary metabolism of sorbus aucuparia cell cultures]. | to investigate the effects of different types of elicitors on the secondary metabolism of sorbus aucuparia cell). | 2014 | 25470952 |
| [mechanism exploration on synthesis of secondary metabolites in sorbus aucuparia cell cultures treated with yeast extract]. | suspension cultures cell of sorbus aucuparia (sasc) was used as materials, the changes of physiological and biochemical indexes of sasc after treatment with yeast extract (ye) were detected, and the synthetic mechanism of secondary metabolites in sasc treated with ye was preliminarily explored. the results were as follows: under the assay conditions, sasc was induced to synthesize five biphenyl compounds, and these compounds content changed differently with induction time prolonging; ye treatmen ... | 2014 | 25272834 |
| tree species composition affects the abundance of rowan (sorbus aucuparia l.) in urban forests in finland. | recent studies have shown a considerable increase in the abundance of rowan (sorbus aucuparia) saplings in urban forests in finland, yet the reasons for this increase are not well understood. here we investigated whether canopy cover or tree species composition, i.e., the basal areas of different tree species in norway spruce dominated urban forests, affects the abundances of rowan seedlings, saplings and trees. altogether 24 urban forest patches were investigated. we sampled the number of rowan ... | 2015 | 25588119 |
| [distribution of hydrocyanic acid in cormophyta: 15.1 new observations on cyanogenesis in rosaceae]. | prunasin was isolated from leaves and roots of aruncus silvester (= a. dioicus), leaves of gillenia trifoliata and seedlings of kageneckia lanceolata (all spiraeoideae). chamaebatiaria millefolium (spiraeoideae - sorbarieae) was found to be cyanogenic; in this instance the cyanogenic constituent seems to be different from prunasin, however. prunasin was isolated also from buds and very young shoots of crataegus irrasa (maloideac - crataegeae). very young leaves of crataegus cuneata and c. pedice ... | 1981 | 17401853 |
| range-body mass interactions of a northern ungulate - a test of hypothesis. | summer diet, summer temperature, length of the growth season and animal density appeared to best explain annual and regional differences in calf and yearling body mass in moose from southeastern norway. in general animals inhabiting steep, alpine landscapes had less body mass than animals using flat, low-altitude habitats. autumn body mass of calves and yearlings decreased with increasing snow depth during the preceding winter and spring. however, calf body mass was more influenced by the summer ... | 1999 | 28307755 |
| how does pollen chemistry impact development and feeding behaviour of polylectic bees? | larvae and imagos of bees rely exclusively on floral rewards as a food source but host-plant range can vary greatly among bee species. while oligolectic species forage on pollen from a single family of host plants, polylectic bees, such as bumblebees, collect pollen from many families of plants. these polylectic species contend with interspecific variability in essential nutrients of their host-plants but we have only a limited understanding of the way in which chemicals and chemical combination ... | 2014 | 24465963 |
| the abundance and pollen foraging behaviour of bumble bees in relation to population size of whortleberry (vaccinium uliginosum). | habitat fragmentation can have severe effects on plant pollinator interactions, for example changing the foraging behaviour of pollinators. to date, the impact of plant population size on pollen collection by pollinators has not yet been investigated. from 2008 to 2010, we monitored nine bumble bee species (bombus campestris, bombus hortorum s.l., bombus hypnorum, bombus lapidarius, bombus pascuorum, bombus pratorum, bombus soroensis, bombus terrestris s.l., bombus vestalis s.l.) on vaccinium ul ... | 2012 | 23209721 |
| essential and non-essential elements in natural vegetation in southern norway: contribution from different sources. | concentrations of essential and non-essential elements in five widespread species of natural boreal vegetation were studied with respect to seasonal variation and contribution from different sources. the plant species included in the study were betula pubescens, sorbus aucuparia, vaccinium myrtillus, vaccinium uliginosum, calluna vulgaris and deschampsia flexuosa. concentrations of elements essential to plants remained essentially constant or decreased slightly throughout the growing season. con ... | 2015 | 25268568 |
| stem co2 efflux in six co-occurring tree species: underlying factors and ecological implications. | stem respiration plays a role in species coexistence and forest dynamics. here we examined the intra- and inter-specific variability of stem co2 efflux (e) in dominant and suppressed trees of six deciduous species in a mixed forest stand: fagus sylvatica l., quercus petraea [matt.] liebl, quercus pyrenaica willd., prunus avium l., sorbus aucuparia l. and crataegus monogyna jacq. we conducted measurements in late autumn. within species, dominants had higher e per unit stem surface area (es ) main ... | 2015 | 25292455 |
| s-allele diversity in sorbus aucuparia and crataegus monogyna (rosaceae: maloideae). | rt-pcr was used to obtain the first estimates from natural populations of allelic diversity at the rnase-based gametophytic self-incompatibility locus in the rosaceae. a total of 20 alleles were retrieved from 20 sorbus aucuparia individuals, whereas 17 alleles were found in 13 crataegus monogyna samples. estimates of population-level allele numbers fall within the range observed in the solanaceae, the only other family with rnase-based incompatibility for which estimates are available. the nucl ... | 2002 | 12180088 |
| screening for new hydroxynitrilases from plants. | we established a simple hplc method to determine the activity and stereochemistry of the chiral mandelonitrile synthesized from benzaldehyde and cyanide, and applied it to screen for hydroxynitrile lyase (hnl) activity of plant origin. a total of 163 species of plants among 74 families were examined for (r)- and (s)-hnl activities using the method. we discovered that homogenate of leaves of baliospermum montanum shows (s)-hnl activity, while leaves and seeds from passiflora edulis, and seeds fro ... | 2005 | 16377893 |
| patterns of late spring frost leaf damage and recovery in a european beech (fagus sylvatica l.) stand in south-eastern germany based on repeated digital photographs. | damage by late spring frost is a risk deciduous trees have to cope with in order to optimize the length of their growing season. the timing of spring phenological development plays a crucial role, not only at the species level, but also at the population and individual level, since fresh new leaves are especially vulnerable. for the pronounced late spring frost in may 2011 in germany, we studied the individual leaf development of 35 deciduous trees (mainly european beech fagus sylvatica l.) at a ... | 2015 | 25759707 |
| plasmodesmata and pit development in secondary xylem elements. | developing pit membranes of secondary xylem elements in drimys winteri, fagus sylvatica, quercus robur, sorbus aucuparia, tilia vulgaris and trochodendron aralioides have been examined by transmission electron microscopy. absence of plasmodesmata from the membranes of vessel elements and tracheids indicates that their pits develop independently of these structures. on the other hand, plasmodesmata are abundant in pit membranes between fibres, parenchyma cells, and combinations of these cell type ... | 1982 | 24271775 |