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PubMed2006

Tree height and age-related decline in growth in Scots pine (Pinus sylvestris L.).

Growth and seasonal water use was measured amongst trees growing in an old growth Scots pine forest in the Scottish Highlands. Three sites which differed in their recent management history and contained old and naturally regenerated young trees growing together were monitored in the field. Our results showed a clear decrease in growth efficiency with age, from values of around 0.25 kg m(-2) leaves year(-1) in approximately 25-year-old trees to less than 0.1 kg m(-2) leaves year(-1) in trees over 200 years old. When the old trees in one of the field sites were released from competition by thinning, their growth efficiency reverted to that of coexisting young trees, indicating that the decline in growth was reversible. This is consistent with the results of a parallel study showing that cambial age had no effect on the physiology or growth of grafted seedlings originating from the same population studied here (Mencuccini et al. 2005). Our detailed study of tree water use in the field showed an overall decrease in whole-tree hydraulic conductance and stomatal canopy conductance with tree height in the unthinned stands, in agreement with the hydraulic limitation hypothesis. However, the effect of this reduction in hydraulic efficiency on growth was comparatively small, and old trees also showed consistently lower nitrogen concentrations in needles, suggesting that hydraulic and nutritional factors combined to produce the decline in growth efficiency with age observed in the studied populations.

Pinus sylvestris↗
PubMed1988

Caries experience in the permanent dentition of late mediaeval Scots (1300-1600 a.d.).

Dental caries prevalence, distribution and site of attack were in broad agreement with previous reports for Mediaeval Scots, namely that caries was principally a disease of adult life and showed a different location distribution from that of modern caries. The findings reinforce evidence that caries prevalence in Scotland was lower than in England at that period. It is suggested that reliable estimates of caries prevalence can best be made by noting: (i) individual caries experience, (ii) lesion location by tooth type and area of attack, (iii) the number of carious teeth of each type as a percentage of teeth of that type present.

Adolescent↗
PubMed1992

Stilbene synthase from Scots pine (Pinus sylvestris).

Stilbene synthases are named according to their substrate preferences. By this definition, enzymes preferring cinnamoyl-CoA are pinosylvin synthases, and proteins with a preference for phenylpropionyl-CoA are dihydropinosylvin synthases. We investigated the assignment of a stilbene synthase cloned from Scots pine (Pinus sylvestris) as dihydropinosylvin synthase and the proposal of an additional pinosylvin synthase [1992, Plant Mol. Biol. 18, 489-503]. The results show that the previous interpretation was misled by several unexpected factors. Firstly, we found that the substrate preference and the activity of the plant-specific protein expressed in E. coli was influenced by bacterial factors. This was reduced by improvement of the expression system, and the subsequent kinetic analysis revealed that cinnamoyl-CoA rather than phenylpropionyl-CoA is the preferred substrate of the cloned stilbene synthase. Secondly, mixing experiments showed that extracts from P. sylvestris contain factor(s) which selectively influenced the substrate preference, i.e. the activity was reduced with phenylpropionyl-CoA, but not with cinnamoyl-CoA. This explained the apparent differences between plant extracts and the cloned enzyme expressed in E. coli. Taken together, the results indicate that the cloned enzyme is a pinosylvin synthase, and there is no evidence for a second stilbene synthase. This study cautions that factors in the natural and in new hosts may complicate the functional identification of cloned sequences.

Acyl Coenzyme A↗
PubMed1989

Regional variation in surface properties of Norway spruce and scots pine needles in relation to forest decline.

Measurements of leaf wettability (contact angle), amounts of epicuticular wax and of surface dust are reported for Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L) Karst) trees growing at 12 sites in Europe from SW Germany to NE Scotland. At each site, three year classes (current year, 1 and 2-year-old) of needles were sampled from the mid-crown of up to 12 trees. Trees were selected at random from two strata, those showing visible decline symptoms (i.e. loss of needles or discoloration) and those apparently healthy. Needles for analysis were taken from apparently healthy (green) shoots in both cases. There were no significant differences between 'declining' and 'healthy' trees within sites, suggesting that leaf surface properties reflect environmental exposure rather than plant response. There were significant differences between sites, particularly for Norway spruce, which may be related to environmental factors including air pollution. Contact angles were consistently smaller at low-altitude sites in Britain and The Netherlands than at high-altitude sites in Germany where forests show decline symptoms. Leaf wettability decreased (contact angles increased) with wax amount and increased with dust amount. Leaf surface properties integrate environmental influences over long periods, and may be useful in identifying sites 'at risk' of developing decline symptoms, but causal relationships cannot be deduced without further direct experimentation.

Journal Article↗
PubMed1991

High nitrogen deposition causes changes in amino acid concentrations and protein spectra in needles of the scots pine (Pinus sylvestris).

Growth of the Scots pine (Pinus sylvestris) suffered considerably in forests close to fur farms in western Finland, with the occurrence of winter time dieback in the youngest shoots and leading to a bush-like, flat crown canopy. One reason for this growth disturbance may be a serious imbalance in nitrogen metabolism caused by the extra N supply, emitted as NH3 from the dung of the animals. Total N and NH4+ concentrations in the needles and soluble nitrogen concentration in the soil increased considerably in the vicinity of the fur farms. The extra N in the needles was bound in the first place in arginine, the concentration of which increased 10(2)-10(3) fold compared with control trees, and to a lesser extent in glutamine and other amino acids. Alterations in the quantitative and qualitative protein patterns of the needles were obtained. The extra N increased the concentration of total soluble proteins, although it inhibited the formation of certain polypeptides (particularly in the areas of 30, 38, 50 and 65-90 kDa) which were possibly essential for the normal wintering processes. One reason for the winter time dieback in the high N area could thus be found in the altered protein profiles.

Journal Article↗
PubMed1991

Combined use of open-air and indoor fumigation systems to study effects of SO2 on leaching processes in Scots pine litter.

Both an open-air fumigation system and a laboratory-based system were used to expose decomposing Scots pine (Pinus sylvestris L.) needles to controlled concentrations of SO(2) (arithmetic mean </= 48 nl litre(-1)) during a period, in total, of 301 days. The experimental design involved reciprocal litter transplants from 'clean' to 'polluted' air and vice versa, using the two fumigation systems. The objectives were (1) to observe the effects of SO(2) on leachate and litter chemistry, (2) to assess whether pollution-induced changes are reversible in clean air, and (3) to test the suitability of small-scale fumigation chambers (litter microcosms) compared with open-air systems in soil studies. Through the formation of SO(4)(2-) ions, dry-deposited SO(2) exhibited a marked capacity to remove 'base' cations (Ca(2+), Mg(2+) and K(+)) from decomposing pine needles, and also to acidify litter leachates (as indicated by proton fluxes from the litter). When litter was transferred from polluted air (48 nl litre(-1) SO(2), in the open-air system) to either clean or polluted air in the laboratory, the effects of prior exposure to SO(2) on leachate composition were still evident even after 86 days: the role of base cation depletion within the litter, caused by SO(4)(2-)-induced leaching, is discussed. Data for SO(4)(2-) fluxes in leachates collected from the small-scale chambers indicated that dry deposition velocities for SO(2) were not anomalously high within this fumigation system. It is therefore concluded that microcosm studies can provide information complementary to the open-air fumigation approach in soils research.

Journal Article↗
PubMed1992

Contribution of canopy leaching to sulphate deposition in a Scots pine forest.

Radioactive sulphate (35SO4) was applied to the soil below a Scots pine forest on 23 June 1989, and its movement into the canopy and into throughfall and stemflow was measured over 4 months. The specific activity, Bq (mg S)(-1), of the canopy increased monotonically; uptake by current-year (1989) expanding needles was initially twice as fast as by older needles or live twigs. By 10 October the canopy average specific activity was 62 Bq (mg S)(-1). The specific activity of net throughfall (throughfall + stemflow - rain), deduced from measurements from six throughfall collectors, six stemflow collectors and two rain collectors, fell rapidly from 12.6 Bq (mg S)(-1) in late July to <1 Bq (mg S)(-1) in mid-August. The results suggest (assuming rapid equilibration of 35S with sulphate in soil) that root-derived sulphate contributed c. 3% of sulphate in net throughfall and that dry deposition of SO2 and sulphate particles contributed c. 97% of the 0.56 g S m(-2) measured in net throughfall over the period. Simultaneous measurements of SO2 at canopy height and of NH3 above and within the canopy gave mean concentrations of 5.9 and 0.86 microg m(-3), respectively, sufficient to account for the sulphate measured in net throughfall only if codeposition of NH3 and SO2 occurred to canopy surfaces. The large values of specific activity observed in July, however, indicate that throughfall composition may be closely related to recent soil input of sulphate, and that equilibrium cannot be safely assumed. The possibility of a significant contribution of soil-derived sulphate to sulphate deposition in net throughfall cannot be ruled out on the basis of this experiment.

Journal Article↗
PubMed1995

Effects of acid rain on growth and nutrient concentrations in Scots pine and Norway spruce seedlings grown in a nutrient-rich soil.

The effects of artificially applied acid precipitation on growth and nutrient concentrations of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies [L.] Karst.) seedlings were investigated in a long-term acid irrigation experiment in field conditions. Seedlings of northern and southern origin were planted in boxes containing peat and composted soil rich in nutrients, and sprinkler irrigated with water acidified with nitric and sulphuric acids to pH 3 or pH 4 for periods varying from two to three and a half growing seasons during 1986-1989. Water irrigated (pH 5.4-7.6) and non-irrigated groups of seedlings were also included in the experiment. At the end of the experiment needles, main and lateral shoots and roots were collected from the seedlings for the determination of height growth and biomass partitioning, and for the analysis of S, N, Mg, P, K, Ca, Mn and Fe concentrations. The treatment effects compared to the irrigated control were studied using multivariate analyses of variance and covariance. In the pine seedlings the total dry matter production increased by 25-70% compared with the irrigated controls when the total wet deposition to the seedlings exceeded 67 kg S ha(-1) and 36 kg N ha(-1) (e.g. after two growing seasons' exposure of the pH 3 treatment). The increase was mainly due to an increase in needle dry weight (54-72% greater at pH 3) and root weight (20-65% greater at pH 3), whereas the height growth or shoot weight growth were less affected. The northern provenance pine seedlings responded more clearly to the pH 3 irrigation than the southern ones. The treatments had no consistent effects on any of the growth variables studied in the spruce seedlings, however. The pines had higher root and foliage Ca concentrations as a result of the acid irrigation, whereas in spruce, acid rain decreased the Ca concentration in needles and shoots. Root Mn and Fe concentrations were higher in both species as a result of the pH 3 treatment. A higher soil conductivity and Ca concentration resulted from the prolonged pH 3 treatment. The results strongly support the hypothesis that the long-term growth and nutrient allocation response of conifers to acid precipitation is dependent both on the tree species and on the nutritional status of the soil.

Journal Article↗
PubMed1996

The effect of simulated acid rain on the biochemical composition of Scots pine (Pinus sylvestris L.) needles.

The effects of prolonged simulated acid rain on the biochemistry of Scots pine needles were studied in Finnish Lapland. Pine trees were exposed by spraying the foliage and soil with either clean water or simulated acid rain (SAR; both sulphuric and nitric acids) over the period 1985-1991. The concentrations of carbohydrates (starch, glucose, fructose, sucrose) in one-year-old pine needles were not affected by SAR-treatments. The SAR-treatments did not have significant effects on protein bound amino acids, which was true also for most of the free amino acids. However, the citrulline concentration was over three-fold greater in the foliage of pines exposed to SAR of pH 3 compared to irrigated controls. The concentrations of total phenolics, individual low molecular weight phenolics and soluble proanthocyanidins were not affected by the treatments, but insoluble proanthocyanidins had increased in acid-treated trees. Some of the studied biochemical compounds showed significant differences between two sub-areas (similar treatments) only 120 m apart.

Journal Article↗
PubMed1996

Assessing the critical level of SO2 for Scots pine in situ.

A field survey was performed in eastern Finland, where measured ambient SO2 concentrations were 1.4-3.8 microg m(-3) a(-1) and bulk S deposition 0.17-0.32 g m(-2) a(-1) in 1991-1993. The accumulation of sulphur (S) in needles of Scots pine (Pinus sylvestris L.) was studied with XRF, IC and FESEM analyses and the needle damage examined under a light microscope and by SEM. Foliar N concentrations were also measured. Foliar total S concentrations were observed to be above the normal S level (500-700 microg g(-1)) over almost the whole area. Slight chlorosis and/or necrosis of the needle tips and stomatal areas, changes in the needle surface waxes and localization of S into needle tips and mesophyll cells around the stomata suggested the impact of S deposition, as did the calculations of St/Nt, and 'predicted' and 'excess' S. A concentration of about 900 microg g(-1) may be considered a critical level for foliar St in areas with low N supply.

Journal Article↗
PubMed1996

Scots pine needle surfaces on radial transects across the north boreal area of Finnish Lapland and the Kola Peninsula of Russia.

To gain an understanding of the characteristics of the needle surfaces of naturally regenerated Scots pine (Pinus sylvestris L.) and their geographical distribution, eight physicochemical variables were investigated within the north boreal forest area. The visibly undamaged needles were collected in autumn 1990 from 114 plots (3-5 pines per plot) along radial transects from the Monchegorsk and Nikel smelters, emitting SO2 and heavy metals, on the Kola Peninsula, Russia, to Finnish Lapland. The needles were examined by scanning electron microscopy (SEM) and measured for surface wettability using the droplet contact angle (DCA) method. Significant geographical south-north and west-east patterns could be observed in needle surface characteristics, correlating with emissions from the smelters and to climate. Despite the slightly higher initial DCAs (61.4-87.6 degrees) towards the north, the pine needle surfaces of the northernmost transects exhibited higher annual needle wettability change (ANWC) and wax erosion rate (AWER), expressed as the reduction in DCAs and epistomatal wax tube distribution (WTD) during one year, respectively, but a lower occurrence of particles and fungal hyphae than those of more southern transects. The higher ANWC was related to higher atmospheric SO2 concentration, and to the lower long-term temperature sum, but not clearly to annual precipitation. In the Monchegorsk smelter area, the current needles exhibited, on average, a 15% higher WTD and seven degree larger DCA, resulting in more hydrophobic needle surfaces than in Finnish Lapland, but during their first year, both the AWER and ANWC, were greatly increased. In Finnish Lapland, 30%, of all the epistomatal wax tubes disappeared from the needle surface during the first year, the value being 70% for the pines located 8 km from the smelter. The mineral composition of the particles deposited on the needle surfaces mirrored that of the minerals being produced by the smelters (e.g. FexSx, CuFeS2, NixSx, FexOx). Stomatal densities were in the range of 71.1-141.7 stomata mm(-2). The lower densities of stomata on needles close to the smelters correlated with reduced number of needle age classes of the pines, higher dry weights, higher pollutant accumulation and lower Mn and Zn concentrations in the needles. The AWER and ANWC were able to indicate the most seriously deteriorated needle surfaces on a regional scale, e.g. including the surroundings of both smelters, although the plot-specific relationships between 'needle surface variables' and 'pollution variables' were generally weak. The present study showed that the exposure of pine needles to the combined effects of ambient pollutants and harsh climate led to a deterioration in the physicochemical characteristics of the epicuticular wax, which may have serious ecophysiological consequences in the long term.

Journal Article↗
PubMed2006

Qualitative and quantitative determination of extractives in heartwood of Scots pine (Pinus sylvestris L.) by gas chromatography.

A method for quantitative determination of extractives from heartwood of Scots pine (Pinus sylvestris L.) using gas chromatography (GC) with flame ionization detection (FID) was developed. The limit of detection (LOD) was 0.03 mg/g wood and the linear range (r = 0.9994) was up to 10 mg/g with accuracy within +/- 10% and precision of 18% relative standard deviation. The identification of the extractives was performed using gas chromatography combined with mass spectrometry (GC-MS). The yields of extraction by Soxhlet were tested for solid wood, small particles and fine powder. Small particles were chosen for further analysis. This treatment gave good yields of the most important extractives: pinosylvin, pinosylvin monomethyl ether, resin acids and free fatty acids. The method is used to demonstrate the variation of these extractives across stems and differences in north-south direction.

Gas Chromatography-Mass Spectrometry↗
PubMed2004

Sulphur dioxide adsorption in Scots pine canopies exposed to high ammonia emissions near a Cu-Ni smelter in SW Finland.

Since 1994 the nickel-processing plant at the Cu-Ni smelter at Harjavalta, south-west Finland, has emitted considerable amounts of NH(3) into the atmosphere. The effects of NH(3) emissions on nitrogen and sulphur deposition in throughfall and the foliar nutrient status were investigated in a Scots pine stand at 0.5 km distance. Bulk deposition, stand throughfall and percolation water (20 cm depth) samples were collected at 4-week intervals during 1992-1998. pH and the Ca, Mg, K, NH(4) and SO(4) concentrations were determined on the samples. NH(3) emissions have strongly increased the scavenging of SO(2) from the air in the pine stand, and the increased levels of N and S deposition were clearly evident as increased foliar N and S concentrations and larger needle size. The increased input of SO(4) into the forest floor was not associated with an increase in the leaching of Ca and Mg from the surface soil layers.

Adsorption↗
PubMed2005

Microfibril angle in wood of Scots pine trees (Pinus sylvestris) after irradiation from the Chernobyl nuclear reactor accident.

The secondary cell wall structure of tracheids of Scots pine (Pinus sylvestris L.), especially the angle of microfibrils in the S(2) layer, was examined in wood deposited prior to and after the Chernobyl accident in 1986. Microscopic analysis was carried out on wood samples collected in October 1997 from breast height of three pine trees 16, 30 and 42 years old. The polluted site was located in a distance of 5 km south from the Chernobyl nuclear power plant where radioactive contamination in 1997 was 3.7 x 10(5) kBq m(-2). Anatomical analysis showed that the structure of the secondary cell wall in tracheids formed after the Chernobyl accident was changed. Changes occurred both in S(2) and S(3) layers. The angle of microfibrils in S(2) layer in wood deposited after the Chernobyl accident was different in comparison to this measured in wood formed prior to the disaster. The intensity of the changes, i.e. alteration of the microfibrils angle in S(2) layer and unusual pattern of the S(3) layer, depended on the age of the tree and was most intensive in a young tree.

Cell Wall↗
PubMed2005

Presence of Nitrosospira cluster 2 bacteria corresponds to N transformation rates in nine acid Scots pine forest soils.

The relation between environmental factors and the presence of ammonia-oxidising bacteria (AOB), and its consequences for the N transformation rates were investigated in nine Scots pine (Pinus sylvestris L.) forest soils. In general, the diversity in AOB appears to be strikingly low compared to other ecosystems. Nitrosospira cluster 2, as determined by temporal temperature gradient electrophoresis and sequencing, was the only sequence cluster detected in the five soils with high nitrification rates. In the four soils with low nitrification rates, AOB-like sequences could not be detected. Differences in nitrification rates between the forest soils correlated to soil C/N ratio (or total N) and atmospheric N deposition.

Ammonia↗
PubMed2005

Uranium distribution and cycling in Scots pine (Pinus sylvestris L.) growing on a revegetated U-mining heap.

We determined the uranium distribution in soil and its allocation in compartments of 35-year-old Scots pine developed on a revegetated U-mining heap. The processes controlling the dynamics of U recycling were identified and further quantified in terms of annual fluxes. As pine developed, an acid humus layer emerged leading to weathering of the alkaline mining debris but this had little effect on U mobility in the soil profile. Increased U mobility mainly involved a translocation of U to metal-humus chelates in surface layers. The root compartment accounted for 99.3% of the U budget in tree, thus serving as an effective barrier which restricts U uptake. The current root uptake and transfer of U to upper parts of the tree amounted to about 3g ha(-1) y(-1), i.e. less than 0.03% of the current NH4-exchangeable U pool in the soil (0-30 cm). Allocation and translocation pattern made it clear that a dominant fraction of the translocated U moves passively with the ascent xylem sap, most likely as a soluble complex, and steadily accumulates in the needles. Consequently, 97% of the U annual uptake is returned to the soil through litterfall. At the studied site, the risk of U dissemination due to biomass turnover or trunk harvest was low when considered in relation to the current "exemption level" for U.

Biodegradation, Environmental↗
PubMed2004

A UV resonance Raman (UVRR) spectroscopic study on the extractable compounds of Scots pine (Pinus sylvestris) wood. Part I: lipophilic compounds.

The wood resin in Scots pine (Pinus sylvestris) stemwood and branch wood were studied using UV resonance Raman (UVRR) spectroscopy. UVRR spectra of the sapwood and heartwood hexane extracts, solid wood samples and model compounds (six resin acids, three fatty acids, a fatty acid ester, sitosterol and sitosterol acetate) were collected using excitation wavelengths of 229, 244 and 257 nm. In addition, visible Raman spectra of the fatty and resin acids were recorded. Resin compositions of heartwood and sapwood hexane extracts were determined using gas chromatography. Raman signals of both conjugated and isolated double bonds of all the model compounds were resonance enhanced by UV excitation. The oleophilic structures showed strong bands in the region of 1660-1630 cm(-1). Distinct structures were enhanced depending on the excitation wavelength. The UVRR spectra of the hexane extracts showed characteristic bands for resin and fatty acids. It was possible to identify certain resin acids from the spectra. UV Raman spectra collected from the solid wood samples containing wood resin showed a band at approximately 1650 cm(-1) due to unsaturated resin components. The Raman signals from extractives in the resin rich branch wood sample gave even more strongly enhanced signals than the aromatic lignin.

Abietanes↗
PubMed2004

Processes, dynamics and modelling of radiocaesium cycling in a chronosequence of Chernobyl-contaminated Scots pine (Pinus sylvestris L.) plantations.

In a large forested area affected by the Chernobyl radioactive fallout, especially in CIS, the lasting recycling of radiocaesium (137Cs) by the trees is a source of long-term contamination of woody products. The quantitative description of the 137Cs dynamics in contaminated forest is a prerequisite to predictive modelling and further management of such territories. Three even-aged mono-specific Scots pine stands (17, 37 and 57 years old) were selected in a contaminated woodland in southeastern Belarus to constitute an adequate chronosequence. We determined the potassium and radiocaesium annual fluxes involved in the biological cycling in each stand using a well-documented calculation methodology. Qualitatively, 137Cs was shown to be rapidly recycled in trees through the same pathways as K and to redistribute similarly between the tree components. Compared to K, a higher fraction of 137Cs, corresponding to about the half of the annual uptake, is immobilised in perennial organs. With tree development, trunk wood and bark become prevailing sinks for 137Cs since they represent an increasing pool of biomass. In the pine chronosequence, the current root absorption, respectively, mobilizes 0.53, 0.32 and 0.31% year(-1) of the total 137Cs pool in soil. Variations in the 137Cs uptake do not reflect differences in the 137Cs balance between stands. In the two older stands, 51 and 71% of the current tree contamination are related to earlier accumulation subsequent to the initial fallout interception and recycling. The soil is the dominant source of long-term tree contamination. A simple modelling based on the measured 137Cs fluxes indicates that, for young stands, radioactive decay-corrected contamination would stabilize after reaching a maximum of 25 years after the 137Cs deposition. Stemwood presents a maximum of 15 years after the deposition and decrease afterwards mainly through radioactive decay. In the older stands, the decontamination is constant without local maximum of 137Cs level in the wood. The 137Cs contamination of tree components is the result of different influential processes like root uptake, internal translocation and immobilisation. For more accurate predictions, the calibration of existing models would be benefited by comparing with the 137Cs annual fluxes instead of the simple transfer factor coefficients. In the perspective of other applications, there is a need of such data for other radionuclides as well as for heavy metals.

Calibration↗