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PubMed2000

Ozone exposure-response relationships for biomass and root/shoot ratio of beech (Fagus sylvatica), ash (Fraxinus excelsior), Norway spruce (Picea abies) and Scots pine (Pinus sylvestris).

Current-year seedlings of beech, ash, Norway spruce and Scots pine were exposed during one growing season to different, but moderate, ozone (O(3)) scenarios representative for Switzerland (50, 85, 100% ambient, 50% ambient+30 nl l(-1)) in open-top chambers (OTCs) and to ambient O(3) concentrations in the field. Biomass significantly decreased with increasing O(3) dose in all species except for spruce. Losses of 25.5% (ash), 17.4% (beech), 9.9% (Scots pine) were found per 10 microl l(-1) h accumulated O(3) exposure over a threshold concentration of 40 nl l(-1) during daylight hours (AOT40). Ratios of root/shoot biomass (RSR) also significantly decreased with increasing AOT40 levels in beech and ash, but not in Norway spruce and Scots pine. The data show that the deciduous species beech and ash were more susceptible to O(3) with respect to RSR and biomass than the coniferous species Norway spruce and Scots pine.

Journal Article↗
PubMed1996

Growth variation of Scots pine across a pollution gradient on the Kola Peninsula, Russia.

Decadal exposure to emissions from a non-ferrous smelter has damaged the forest ecosystems surrounding the city of Monchegorsk located on the Kola Peninsula in northwestern Russia. We use the methods of tree-ring analysis to study the areal extent and timing of recent growth reductions of Scots pine (Pinus sylvestris L.) in the region surrounding the smelter in Monchegorsk. Reduced growth of Scots pine was observed up to 30 km southwest of the smelter. This directional gradient of forest damage is related to the dispersal of pollutants which is influenced by the prevailing northern winds and local topographic features. Old Scots pines (age 200 years +) appeared to be more sensitive than younger ones: growth reductions of old trees had started earlier and reductions were observed farther from the smelter than for younger trees. The findings are compared to a classification which describes the state of forest ecosystems based on the occurrence of certain plant species; the classification matched well with the observed growth trends. Pollution-induced changes in the climatic signal in tree-rings are also studied. The strong dependence of growth on mid-summer temperatures, typical for Scots pine on high latitudes, proved to be insensitive to effects of pollution. Changes in the climate-growth relationship took place decades after growth trends had started to decline.

Journal Article↗
PubMed1999

The effects of UV exclusion on the soluble phenolics of young Scots pine seedlings in the subarctic.

The characteristics of UV-absorbing compounds, particularly soluble phenolics, were studied in needles of 63-day-old seed-grown Scots pine (Pinus sylvestris L.) seedlings of two provenances in a UV exclusion field experiment at Pallas-Ounastunturi National Park in Finnish Lapland (68 degrees N, 270 m a.s.l.). The experiment used the following plastic filters in exclosure treatments to manipulate the spectral balance of natural irradiance: (1) 'control' (a polyethene plastic filter); (2) 'UV-B exclusion' (a clear polyester filter); and (3) 'UV-B/UV-A exclusion' (a clear acryl plate). Polyethene transmitted 89% of the ambient levels of total UV (280-400 nm), polyester transmitted 75% of the total UV, but only 0.6% of the UV-B (280-315 nm) component, while acryl plate transmitted 0.2% of UV (280-360 nm). The research also included (4) 'Ambient' plants that were not subjected to any treatment exclosures. After the 58 day UV exclusion, significant (p<0.0001) differences due to treatments were determined for a kaempferol derivative, kaempferol 3-glucoside, and a quercetin derivative, the quantities of which ranged from 0.23 to 0.45, 0.42 to 1.34 and 0.39 to 0.75 micromol g FW(-1), respectively, depending on treatment and provenance. Overall, Scots pine seedlings grown at ambient UV radiation (PAS300, Caldwell's generalized Plant Action Spectrum (PAS) normalized at 300 nm, 72 mW m(-2)) or under a control had significantly (p<0.05) higher quantities of soluble phenolics than seedlings grown under UV-B or UV-B/UV-A exclusion treatments. There were no significant differences in the quantity of soluble phenolics between the two exclosure treatments or between the two Scots pine provenances. The sums of diacylated flavonol glucosides ranging from 3.75 to 4.55 micromol g FW(-1) depending on treatment and provenance, were already present at very low UV-levels under the UV-B/UV-A exclusion treatment. The present study indicated that soluble phenolics, particularly the diacylated flavonol glucosides, may provide an effective preformed protection for young Scots pine seedlings against UV-B and UV-A radiation.

Journal Article↗
PubMed1999

The effects of multiple metal contamination on ectomycorrhizal Scots pine (Pinus sylvestris) seedlings.

Experiments were conducted to investigate the effects of single and multiple metal contamination (Cd, Pb, Zn, Sb, Cu) on Scots pine seedlings colonised by ectomycorrhizal (ECM) fungi from natural soil inoculum. Seedlings were grown in either contaminated field soil from the site of a chemical accident, soils amended with five metals contaminating the site, or in soil from an uncontaminated control site. Although contaminated and metal-amended soil significantly inhibited root and shoot growth of the Scots pine seedlings, total root tip density was not affected. Of the five metals tested in amended soils, Cd was the most toxic to ECM Scots pine. Field-contaminated soil had a toxic effect on ECM fungi associated with Scots pine seedlings and caused shifts in ECM species composition on ECM seedlings. When compared to soils amended with only one metal, soils amended with a combination of all five metals tested had lower relative toxicity and less accumulation of Pb, Zn and Sb into seedlings. This would indicate that the toxicity of multiple metal contamination cannot be predicted from the individual toxicity of the metals investigated.

Journal Article↗
PubMed2003

Drought stress alters the concentration of wood terpenoids in Scots pine and Norway spruce seedlings.

Drought is known to have an impact on the resistance of conifers to various pests, for example, by affecting resin flow in trees. Little is known, however, about the quantitative and qualitative changes in resin when trees are growing in low moisture conditions. We exposed Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) seedlings to medium and severe drought stress for two growing seasons and analyzed the monoterpenes and resin acids in the main stem wood after two years of treatment. In addition to secondary chemistry, we measured the level of nutrients in the needles and the growth response of seedlings. After the first year of treatment, drought stress did not affect the growth of seedlings, but in the second year, shoot growth was retarded, especially in Scots pine. In both conifer species, severe drought increased the concentrations of several individual monoterpenes and resin acids. Total monoterpenes and resin acids were 39 and 32% higher in severe drought-treated Scots pine seedlings than in the controls, and 35 and 45% higher in Norway spruce seedlings. In Scots pine needles, the concentrations of nitrogen and phosphorus increased, while magnesium and calcium decreased compared to controls. In Norway spruce needles, nutrient concentrations were not affected. The results suggest that drought stress substantially affects both the growth of conifers and the chemical quality of the wood. We discuss the potential trade-off in growth and defense of small conifer seedlings.

Adaptation, Physiological↗
PubMed2004

Development of a structured clinical operative test (SCOT) in the assessment of practical ability in the oral surgery undergraduate curriculum.

Competence in undergraduate oral surgery involves assessment of the students' knowledge, practical skill and attitude. The assessment of practical skills can be achieved using a formative assessment method such as the structured clinical operative test (SCOT) which uses a checklist for the assessment of a clinical task. The aim of this study was primarily to determine whether SCOTs could be integrated into the oral surgery undergraduate course, and secondarily to collect feedback from both the students and the staff on this assessment. A validated checklist was used by trained examiners to assess the performance of 49 students in their second clinical year undertaking simple exodontia. Feedback was collected from the students by questionnaire and from the staff by interview. The SCOT was well received by both students and staff. The main problem highlighted by the students was the perceived inter-examiner variability and by the staff, the disruptive effect on the clinics. The checklist must be objective enough to prevent misinterpretation. Despite these limitations, the SCOT provides a more objective assessment and serves to highlight weaker students, allowing them to be targeted for closer supervision and instruction as well as providing the students with a tool to measure their progress in oral surgery. The use of peer assessment by students may alleviate the burden on the staff.

Clinical Competence↗
PubMed2004

Regulation of organic and inorganic nitrogen uptake in Scots pine (Pinus sylvestris) seedlings.

Plants possess regulatory mechanisms that enhance nitrogen (N) uptake under conditions of spatial and temporal variation in N availability. Study of regulatory mechanisms has focused almost exclusively on the uptake of inorganic N sources (i.e., ammonium (NH4+), nitrate (NO3-). Several lines of evidence, however, suggest that amino acids may constitute a potential source of N for a number of plant species, including conifers. In the present study, we investigated the uptake of amino acids and inorganic N in Scots pine (Pinus sylvestris L.) seedlings grown at different N concentrations. We compared the uptake rate of the individual N sources using U-[13C2], [15N]-glycine, U-[13C6], [15N4]-arginine, 15NH4, or 15NO3, and tested the short-term effect of N supply on the uptake rate of glycine, arginine and in field-grown Scots pine seedlings. Our data indicate that Scots pine seedlings can absorb substantial amounts of N in the form of intact arginine and glycine molecules. The data also suggest that Scots pine seedlings down-regulate their uptake of NH4+-N and arginine-N, but not of glycine-N in response to increased endogenous N concentrations.

Nitrogen↗
PubMed2006

Anatomical-based defense responses of Scots pine (Pinus sylvestris) stems to two fungal pathogens.

We investigated the cellular responses of stem tissues of mature Scots pine (Pinus sylvestris L.) trees to inoculations with two fungal pathogens. The bark beetle vectored fungus, Leptographium wingfieldii Morelet, induced longer lesions in the bark, stronger swelling of polyphenolic parenchyma cells, more polyphenol accumulation and increased ray parenchyma activity compared with the root rot fungus, Heterobasidion annosum (Fr.) Bref., or mechanical wounding. Axial resin ducts in the xylem are a general feature of the preformed defenses of Scots pine, but there was no clear induction of additional traumatic axial resin ducts in response to wounding or fungal infection. The anatomical responses of Scots pine to pathogen infection were localized to the infection site and were attenuated away from bark lesions. The responses observed in Scots pine were compared with published studies on Norway spruce (Picea abies (L.) Karst.) for which anatomically based defense responses have been well characterized.

Ascomycota↗
PubMed2002

Mycobacterium avium genes expressed during growth in human macrophages detected by selective capture of transcribed sequences (SCOTS).

Selective capture of transcribed sequences (SCOTS) has been employed to identify 54 cDNA molecules that represent 46 genes that are expressed by Mycobacterium avium during growth in human macrophages. Some cDNA molecules correspond to genes that are apparently expressed 48 h after infection of macrophages, while others correspond to genes expressed 110 h after infection, and still others correspond to genes expressed throughout the course of infection in our model system. Genes expressed by M. avium during growth in macrophages include genes encoding enzymes of several biosynthetic pathways (pyrimidines, mycobactin, and polyketides); genes that encode enzymes involved in intermediary metabolism, energy metabolism (tricarboxylic acid cycle, glyoxalate shunt), and nitrogen metabolism; and genes that encode regulatory proteins. A number of genes of unknown function were also identified, including genes that code for proteins similar to members of the PPE family of proteins of Mycobacterium tuberculosis and proteins similar to those encoded by the M. tuberculosis mce genes, which have been previously associated with mycobacterial virulence. The SCOTS technique, followed by enrichment for cDNA molecules that are up-regulated or are uniquely expressed by M. avium during growth in human macrophages (compared to growth in laboratory broth culture), allows recovery and identification of a greater diversity of cDNA molecules than does subtractive hybridization between cDNA mixtures from macrophage-grown and broth-grown M. avium. Data are presented demonstrating the reproducibility of recovery of a subset of cDNA molecules from cDNA mixtures purified by SCOTS on several different occasions. These results further demonstrate the beneficial utility of the SCOTS technique for identifying genes whose products are needed for successful survival and growth by an organism in a specific environment.

Cloning, Molecular↗
PubMed2006

Predicting the decomposition of Scots pine, Norway spruce, and birch stems in Finland.

Models were developed for predicting the decomposition of dead wood for the main tree species in Finland, based on data collected from long-term thinning experiments in southern and central Finland. The decomposition rates were strongly related to the number of years after tree death. In contrast to previous studies, which have used the first-order exponential model, we found that the decomposition rate was not constant. Therefore, the Gompertz and Chapman-Richard's functions were fitted to the data. The slow initial decomposition period was mainly due to the fact that most dead trees remained standing as snags after their death. The initial period was followed by a period of rapid decomposition and, finally, by a period of moderately slow decomposition. Birch stems decomposed more rapidly than Scots pine and Norway spruce stems. Decomposition rates of Norway spruce stems were somewhat lower than those of Scots pine. Because the carbon concentration of decaying boles was relatively stable (about 50%) the rate of carbon loss follows that of mass loss. Models were also developed for the probability that a dead tree remains standing as a snag. During the first years after death, the probability was high. Thereafter, it decreased rapidly, the decrease being faster for birch stems than for Scots pine and Norway spruce stems. Almost all stems had fallen down within 40 years after their death. In Scots pine and Norway spruce, most snags remained hard and belonged to decay class 1. In birch, a higher proportion of snags belonged to the more advanced decay classes. The models provide a framework for predicting dead wood dynamics in managed as well as dense unthinned stands. The models can be incorporated into forest management planning systems, thereby facilitating estimates of carbon dynamics.

Betula↗
PubMed1992

Characterization of cDNAs encoding CuZn-superoxide dismutases in Scots pine.

A Scots pine (Pinus sylvestris L.) cDNA library was screened with two heterologous cDNA probes (P31 and T10) encoding cytosolic and chloroplastic superoxide dismutases (SOD) from tomato. Several positive clones for cytosolic and chloroplastic superoxide dismutases were isolated, subcloned, mapped and sequenced. One of the cDNA clones (PS3) had a full-length open reading frame of 465 bp corresponding to 154 amino acid residues and showed approximately 85% homology with the amino acid sequences of angiosperm cytosolic SOD counterparts. Another cDNA clone (PST13) was incomplete, but encoded a putative protein with 93% homology to pea and tomato chloroplastic superoxide dismutase. The derived amino acid sequence from both cDNA clones matched the corresponding N-terminal amino acid sequence of the purified mature SOD isozymes. Northern blot hybridizations showed that, cytosolic and chloroplastic CuZn-SOD are expressed at different levels in Scots pine organs. Sequence data and Southern blot hybridization confirm that CuZn-SODs in Scots pine belong to a multigene family. The results are discussed in relation to earlier observations of CuZn-SODs in plants.

Amino Acid Sequence↗
PubMed1991

Evolutionary conservation of the chlorophyll a/b-binding proteins: cDNAs encoding type I, II and III LHC I polypeptides from the gymnosperm Scots pine.

cDNAs encoding three different LHC I polypeptides (Type I, Type II and Type III) from the gymnosperm Scots pine (Pinus sylvestris L.) were isolated and sequences. Comparisons of the deduced amino acid sequences with the corresponding tomato sequences showed that all three proteins were highly conserved although less so than the LHC II proteins. The similarities between mature Scots pine and tomato Types I, II and III LHC I proteins were 80%, 87% and 85%, respectively. Two of the five His residues that are found in AXXXH sequences, which have been identified as putative chlorophyll ligands in the Type I and Type II proteins, were not conserved. The same two regions of high homology between the different LHC proteins, which have been identified in tomato, were also found in the Scots pine proteins. Within the conserved regions, the Type I and Type II proteins had the highest similarity; however, the Type II and Type III proteins also showed a similarity in the central region. The results suggest that all flowering plants (gymnosperms and angiosperms) probably have the same set of LHC polypeptides. A new nomenclature for the genes encoding LHC polypeptides (formerly cab genes) is proposed. The names lha and lhb are suggested for genes encoding LHC I and LHC II proteins, respectively, analogous to the nomenclature for the genes encoding other photosynthetic proteins.

Amino Acid Sequence↗
PubMed2005

Characterization of the photosynthetic apparatus in cortical bark chlorenchyma of Scots pine.

Winter-induced inhibition of photosynthesis in Scots pine (Pinus sylvestris L.) needles is accompanied by a 65% reduction of the maximum photochemical efficiency of photosystem II (PSII), measured as Fv/Fm, but relatively stable photosystem I (PSI) activity. In contrast, the photochemical efficiency of PSII in bark chlorenchyma of Scots pine twigs was shown to be well preserved, while PSI capacity was severely decreased. Low-temperature (77 K) chlorophyll fluorescence measurements also revealed lower relative fluorescence intensity emitted from PSI in bark chlorenchyma compared to needles regardless of the growing season. Nondenaturating SDS-PAGE analysis of the chlorophyll-protein complexes also revealed much lower abundance of LHCI and the CPI band related to light harvesting and the core complex of PSI, respectively, in bark chlorenchyma. These changes were associated with a 38% reduction in the total amount of chlorophyll in the bark chlorenchyma relative to winter needles, but the Chl a/b ratio and carotenoid composition were similar in the two tissues. As distinct from winter pine needles exhibiting ATP/ADP ratio of 11.3, the total adenylate content in winter bark chlorenchyma was 2.5-fold higher and the estimated ATP/ADP ratio was 20.7. The photochemical efficiency of PSII in needles attached to the twig recovered significantly faster (28-30 h) then in detached needles. Fluorescence quenching analysis revealed a high reduction state of Q(A) and the PQ-pool in the green bark tissue. The role of bark chlorenchyma and its photochemical performance during the recovery of photosynthesis from winter stress in Scots pine is discussed.

Adenosine Diphosphate↗
PubMed2005

Connections between climatic variables and the growth and needle dynamics of Scots pine (Pinus sylvestris L.) in Estonia and Lapland.

The relationships between climatic variables and Scots pine (Pinus sylvestris L.) growth and needle dynamics were studied in three stands in Estonia and in four stands located near the northern timberline in Lapland. The trees sampled in Estonia had low correlations with the analysed climatic variables (air temperature, precipitation and indices of atmospheric circulation). Moreover, the weak cross-correlation of the time-series of the Estonian sample trees indicated that Scots pine is affected mainly by local factors in that region. In Lapland, however, height increment and needle production correlated strongly among trees within a stand (mean r=0.45 and 0.46, respectively) and between stands (r=0.32 and 0.37). Radial increment also showed a high inter-correlation among the trees within a stand in Lapland (r=0.45). Both height increment and needle production were strongly influenced by the temperature regime of the previous summer in Lapland (mean r=0.64 and 0.64, respectively). Radial increment was correlated with the mean July temperature of the current year (mean r=0.29). The correlations between the indices of atmospheric circulation and tree attributes were weak, while the strongest correlation was between the Ponta Delgada NAO index (PD-NAO) and height increment and needle production in Lapland. Height increment, needle production and radial increment have increased since the 1990s in the trees growing in Lapland. This may indicate a positive effect of climate warming on tree growth in Lapland. In Estonia, where climatic conditions do not limit tree growth, the climate warming seems not to directly influence the growth and needle dynamics of Scots pine.

Climate↗
PubMed2006

Long-term exposure to enhanced UV-B radiation has no significant effects on growth or secondary compounds of outdoor-grown Scots pine and Norway spruce seedlings.

The effects of long-term enhanced UV-B radiation on growth and secondary compounds of two conifer species were studied in an outdoor experiment. Scots pine (Pinus sylvestris) seedlings were exposed for two growing seasons and Norway spruce (Picea abies) seedlings for three growing seasons to supplemental UV-B radiation, corresponding to a 30% increase in ambient UV-B radiation. The experiment also included appropriate controls for ambient and increased UV-A radiation. Enhanced UV-B did not affect the growth of the conifer seedlings. In addition, neither the concentrations of terpenes and phenolics in the needles nor the concentrations of terpenes in the wood were affected. However, in the UV-A control treatment the concentrations of diterpenes in the wood of Scots pine decreased significantly compared to the ambient control. Apparently, a small increase in UV-B radiation has no significant effects on the secondary compounds and growth of Scots pine and Norway spruce seedlings.

Environmental Monitoring↗
PubMed2006

A 6-bp deletion at the splice donor site of the first intron resulted in aberrant splicing using a cryptic splice site within exon 1 in a patient with succinyl-CoA: 3-Ketoacid CoA transferase (SCOT) deficiency.

Succinyl-CoA: 3-ketoacid-CoA transferase (SCOT; locus symbol OXCT, EC 2.8.3.5) deficiency is a rare genetic disorder affecting ketone body utilization in extra-hepatic tissues. A 6-bp deletion at the splice donor site of intron 1 resulted in the absence of a full-length mature SCOT mRNA with faint amounts of aberrantly spliced transcripts using a cryptic splice donor site within exon 1, which was located just 7 bases upstream from the authentic site in a SCOT deficient patient.

Base Pairing↗
PubMed2002

Historical changes in lead concentrations in tree-rings of sycamore, oak and Scots pine in north-west England.

Lead concentrations in tree rings of sycamore (Acer pseudoplatanus L.), oak (Quercus robur L.) and Scots pine (Pinus sylvestris L.) sampled at a parkland in north-west England were measured in wood formed since the mid-1800s. Concentrations of Pb in Scots pine and oak peaked in wood formed between 1900 and 1940, most likely because of Pb accumulation in heartwood, indicating that oak and Scots pine are unsuitable for monitoring temporal changes in Pb deposition at the study site. In contrast, Pb concentrations in sycamore, a species that has similar heartwood and sapwood chemistry, were relatively constant in wood formed between the mid-1800s and 1950. Lead concentrations decreased steadily in sycamore tree rings formed after the 1950s, and decreased more abruptly in wood formed after 1985. This sharp decrease in wood Pb cannot be due to decreases in soil Pb concentration. Stable Pb isotope analysis was used to further investigate Pb patterns in sycamore wood. Excess 206Pb/207Pb ratios in tree-rings of sycamore were relatively constant, approximately 1.17, in wood formed prior to the 1930s, but decreased steadily thereafter reaching a minimum value of approximately 1.16 in wood formed between 1975 and 1985 after which time 206Pb/207Pb ratios increased. This pattern is consistent with changes in Pb isotope ratios measured in peat, sediment and aerosol samples in the UK. However, the magnitude of the decrease in 206Pb/207Pb (largely due to gasoline Pb) is considerably lower than in other studies and our estimates indicate that less than 20% of the total Pb in sycamore wood measured since the mid-1800s is derived from gasoline emissions. A more likely explanation for the pattern of Pb observed in sycamore tree rings is that soil Pb accumulates within rings of the diffuse porous wood over a number of years. Such uptake patterns would result in lower Pb concentrations in the outer (more recently formed) tree rings, which coincide with recent reductions in Pb deposition in the UK. Overall, this study indicates that tree ring chemistry is unsuitable for monitoring historical changes in Pb deposition at the study site.

Air Pollutants↗
PubMed2003

Isolation of a novel antimicrobial peptide gene (Sp-AMP) homologue from Pinus sylvestris (Scots pine) following infection with the root rot fungus Heterobasidion annosum.

A new family of antimicrobial peptide homologues termed Sp-Amp has been discovered in Pinus sylvestris (Scots pine). This is the first report of such proteins to be characterized in a conifer species. Sp-AMP1 was identified in a substructured cDNA library of root tissue infected with the root rot fungus Heterobasidion annosum and encodes a mature peptide of 79 amino acid residues. Three additional members of the Sp-AMP family (Sp-AMPs 2-4) encode cysteine-rich proteins of 105 amino acids, each containing an N-terminal region with a probable cleavage signal sequence. Northern analysis confirmed that Sp-AMP expression is elevated in Scots pine roots upon infection with H. annosum. These peptides share 64% amino acid identity with a mature protein from Macadamia integrifolia (MiAMP1), which allowed us to build a homology model for preliminary analysis. Southern analyses further confirmed that several copies of the gene are present in the Scots pine genome. The potential significance of Sp-AMP in the H. annosum-conifer pathosystem is discussed.

Antimicrobial Cationic Peptides↗