首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 93 毫秒
1.
We tested the hypothesis that compensatory fertilization of Scots pine (Pinus sylvestris L.) stands polluted by theHarjavalta copper-nickel smelter in SW Finland alleviates thestress imposed by metal-contaminated soils. The treatments inthe experiment consisted of control, liming, slow-release mineral mixture and stand-specific fertilization, which comprised at least methylene urea and ammonium nitrate. Stresswas assessed by needle fluctuating asymmetry (FA) which increases with an increase in developmental instability. Sevenyears after the treatments, we found pronounced variation inboth FA and needle length among study sites (0.5, 2, 4 and 8 km from the smelter) and among treatments. FA increased and needlelength decreased with proximity to the pollution source. Variation in FA was independent of tree size (used as index ofgrowth rate in even-age stand); the effects of the treatmentson needle length, on the other hand, were expressed only inmedium-sized and large trees. Liming best alleviated pollutionstress, while the application of a slow-release mineral mixtureincreased FA by 30%. In pollution-stressed stands FA correlatedpositively with constitutive resin flow but was independent of volume growth. Our findings suggest that physiological stress (indicated by increase in developmental instability) and tree growth or stand productivity are not directly linked to one another, and that some increase in productivity can be achievedwithout the alleviation of pollution-induced stress.  相似文献   

2.
Decomposition of unpolluted Scots pine needle litter was studied in two heavy-metal-pollution gradients in Sweden; one near a brass mill and the other around a primary smelter. In the latter area locally collected polluted Scots pine needle litter was also incubated. Decomposition rates were strongly influenced by the metal pollution and a decrease in the rate of mass-loss occurred. In the brass-mill gradient this occurred until about 1 km from the pollution source which corresponded to about 500 µg Cu and 1 000 µg Zn g?1 soil. Data are presented to indicate that lignin decomposition was more sensitive to pollution than decomposition of whole litter and affected further away from the pollution sources. At the smelter sites, the metal-polluted needle litter decomposed more slowly than the unpolluted needle litter, and this difference was enhanced close to the smelter. The results indicate that heavy metals accumulated in needles prior to shedding have a long-term impact on the subsequent decomposition of the litter. Both litter quality and soil factors thus contribute to the reduced litter decomposition rate in metal-polluted forests. A new non-linear model with decreasing decay rate was used in the statistical evaluation. The model can be used to characterize the effects of pollution on decomposition rate.  相似文献   

3.
In the early summer of 1987 an untimely needle loss was observed in Scots pine (Pinus sylvestris L.) of different ages growing on oliogotrophic mineral soils in Cladina and Calluna-type heath forests in northern Finland. The first symptoms were observed at the beginning of July when current shoot growth was ending and the young needles were flushing. The older needles first yellowed then later turned brown before falling. Needle loss proceeded from the oldest to the younger needle age classes. The trees lost between one and four age classes of needles from earlier growth and retained only the most recent 1 to 3 yr needles. Foliar analysis indicated nutrient stress as revealed by retranslocation of mobile nutrients such as N and insufficient uptake of immobile nutrients such as Ca. The soil nutrient concentration, however, was normal at poor sites and therefore it appears the primary reason for needle Loss is a nutrient stress due to root damage. This damage was caused by unusual weather in the winter of 1986 to 1987, rather than by soluble Al.  相似文献   

4.
In the early summer of 1987 an untimely needle loss was observed in Scots pine (Pinus sylvestris L.) of different ages growing on oliogotrophic mineral soils in Cladina and Calluna-type heath forests in northern Finland. The first symptoms were observed at the beginning of July when current shoot growth was ending and the young needles were flushing. The older needles first yellowed then later turned brown before falling. Needle loss proceeded from the oldest to the younger needle age classes. The trees lost between one and four age classes of needles from earlier growth and retained only the most recent 1 to 3 yr needles. Foliar analysis indicated nutrient stress as revealed by retranslocation of mobile nutrients such as N and insufficient uptake of immobile nutrients such as Ca. The soil nutrient concentration, however, was normal at poor sites and therefore it appears the primary reason for needle loss is a nutrient stress due to root damage. This damage was caused by unusual weather in the winter of 1986 to 1987, rather than by soluble Al.  相似文献   

5.
Bäck  Jaana  Turunen  Minna  Ferm  Ari  Huttunen  Satu 《Water, air, and soil pollution》1997,100(1-2):119-132
Scots pine (Pinus sylvestris) needles from forest sites differing in distance from big fur farms emitting large amounts of ammonia and ammonium (=NHy) were examined by scanning and transmission electron microscopy. Specific features indicating an ammonium-nitrogen overload, such as an abundance of needle surface organisms and modifications in cellular and wax structures, were classified. Throughout the study area (up to 1000 m from the farms), mesophyll cells had thin cytoplasm and folding plasmalemma indicating frost damage. Phloem damage attributable to a possible nutrient imbalance was also observed. Chloroplast membranes were undulating and the occurrence of leaf surface organisms (e.g. aerophilic algae) was more abundant at the closest sites. The changes were related both to the direct effects of dry NHy deposition on the needles, and to the effects operating via soil acidification. The needle epicuticular waxes proved to be structurally rather inert against the influence of ammonium compounds, since no significant changes due to NHy were observed.  相似文献   

6.
The concentration of fluoride in needles, its effects on tree defoliation and on decomposition of needles (litter), and its subsequent accumulation in the upper soil horizons were observed in pine plantations near and far from a new aluminum smelter. Pinus taeda and Pinus palustris stands within 0.8 km of the smelter had significantly higher levels of foliar F than a P. taeda stand 1.8 km from the source. Neither temporal patterns nor amounts of needlefall were altered by airborne F from the smelter. In addition, elevated levels of foliar F did not affect the rate of decomposition of pine needles over a period of 6 mo. Soluble F in soil samples increased significantly in the upper 10 cm of the soils at the sites nearest the F source over a period of 7 yr since the start of F emissions.  相似文献   

7.
Microbial biomass C and N, and activities related to C and N cycles, were compared in needle and leaf litter, and in the uppermost 10 cm of soil under the litter layer in Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L.) and silver birch (Betula pendula L.) stands, planted on originally similar field afforestation sites 23–24 years ago. The ground vegetation was differentiated under different tree species, consisting of grasses and herbs under birch and pine, and mosses or no vegetation with a thick layer of needles under spruce. The C:N ratio of the soils was 13–21 and the soil pHCaCl 2 3.8–5.2. Both showed little variation under different tree species. Microbial biomass C and N, C mineralization, net ammonification, reduction) did not differ significantly in soil under different tree species either. Birch leaf litter had a higher pHCaCl 2 (5.9) than spruce and pine needle litter (pH 5.0 and 4.8, respectively). The C:N ratio of spruce needles was 30, and was considerably higher in pine needles (69) and birch leaves (54). Birch leaves tended to have the highest microbial biomass C and C mineralization. Spruce needles appeared to have the highest microbial biomass N and net formation of mineral N, whereas formation of mineral N in pine needles and birch leaves was negligible. Microbial biomass C and N were of the same order of magnitude in the soil and litter samples but C mineralization was tenfold higher in the litter samples.  相似文献   

8.
Peat and needle samples were collected from an old Cu, Zn and Ni ore-prospecting experiment at Alkkia, SW Finland. The element rates applied were 100–400 kg ha-1 for Ni and 100–1000 kg ha-1 for Cu and Zn. The heavy metal toxicity of Scots pine stand was estimated primarily on the basis of stand mortality during 28 yr. The tolerance limit values were applied to pine stands growing along a Cu-Ni deposition gradient (0.9–10 km) at Harjavalta copper smelter, SW Finland. Very high heavy metal concentrations in the pine needles and strong accumulation in the surface humus and uppermost peat layers were found. A Cu concentration of 840, Ni 180 and Zn 220 mg kg-1 in peat 0–10 cm, and a Cu concentration of 50, Ni 30 and Zn 175 mg kg-1 in the current needles of the uppermost whorl are proposed as toxicity limits for peatland forests at Harjavalta. According to the heavy metal amounts in peat 0–20 cm, the toxicity area for Cu extended to a distance of 2.0 km, for Ni about 1.0 km and for Zn 0.4 km to the west of the emission point source.  相似文献   

9.
《Soil biology & biochemistry》2001,33(4-5):683-687
Emissions of N2O from acid coniferous forest soils are found to be low and considered to be due to nitrification rather than denitrification. Recently we have demonstrated soil-layer specific denitrification in a Scots pine forest in the Netherlands. N2O production, in the presence of high concentrations of acetylene, was detected in the intact needle fraction but was absent in the fragmentation layer of this forest soil. To identify the factors regulating denitrification activity, in the present study the effects of oxygen, pH and organic carbon were investigated in the needle and fragmentation fraction of acid coniferous forest soils. Under natural circumstances denitrification in the Scots pine needles was higher than in Douglas fir needles and absent in fragmentation material. Under anaerobic conditions comparable N2O production in the two soil types was found in needle suspensions of both forest types, indicating that differences in anaerobic microsites were responsible for different N2O production under aerobic circumstances. Denitrifying capacity was absent in the fragmentation layer; under anaerobic circumstances little N2O was produced. Neither an addition of available carbon (glucose and succinate) nor an increase in pH revealed a denitrifying capacity comparable to that observed in needles. The increase in pH, under anaerobic circumstances, was most effective on N2O production in the fragmentation material. The denitrifying capacity in the fragmentation layer remained low during short-term incubation under optimal conditions. This indicates the presence of a low denitrifying population, most likely due to aerobic conditions, low pH and low available organic carbon. Although the significance of N2O production under natural conditions remains speculative, this study seeks to clarify soil-layer specific denitrifying activity in acid coniferous forest soils.  相似文献   

10.
Air pollution induced changes in pine needle chemistry were observed at sample sites in the surroundings of the Pechenganikel smelter. Close to the smelter, elevated concentrations of Ni, Cu and S were found (Ni: 0.7–1 mmol/kg, Cu: 0.4–0.5, and S 40–60 mmol/kg). Close to the pollution source, needles were enriched in Ni and Cu by needle age. Correlation and principal component analyses show that changes in the element composition of pine needles depended on air pollution and on natural factors as well. The contribution from air pollution increased with needle age. Besides direct input of pollutants from atmosphere, soil contamination and nutritional disturbance contributed significantly to the observed changes.  相似文献   

11.
Microbial biomass C and N, and activities related to C and N cycles, were compared in needle and leaf litter, and in the uppermost 10 cm of soil under the litter layer in Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L.) and silver birch (Betula pendula L.) stands, planted on originally similar field afforestation sites 23–24 years ago. The ground vegetation was differentiated under different tree species, consisting of grasses and herbs under birch and pine, and mosses or no vegetation with a thick layer of needles under spruce. The C:N ratio of the soils was 13–21 and the soil pHCaCl 2 3.8–5.2. Both showed little variation under different tree species. Microbial biomass C and N, C mineralization, net ammonification, reduction) did not differ significantly in soil under different tree species either. Birch leaf litter had a higher pHCaCl 2 (5.9) than spruce and pine needle litter (pH 5.0 and 4.8, respectively). The C:N ratio of spruce needles was 30, and was considerably higher in pine needles (69) and birch leaves (54). Birch leaves tended to have the highest microbial biomass C and C mineralization. Spruce needles appeared to have the highest microbial biomass N and net formation of mineral N, whereas formation of mineral N in pine needles and birch leaves was negligible. Microbial biomass C and N were of the same order of magnitude in the soil and litter samples but C mineralization was tenfold higher in the litter samples.  相似文献   

12.
Total S concentrations in Scots pine (Pine sylvestris L.) needles and the lichen Hypogymnia physodes collected from the vicinity of an oil refinery in southern Finland and a steel works in northern Finland were used as a bioindicator for SO2 deposition. The mean total S concentration in the youngest pine needles decreased by 22% (p <0.001) and that of the second youngest needles by 28% (p < 0.001) as emissions from the oil refinery were reduced by nearly 50% from 1980 to 1985. Total S concentration in both needles and lichens were higher in the vicinity of the oil refinery due to the greater influence of long-range transport S deposition in southern Finland. The two industrial plants had approximately equal SO2 emissions in 1985. The results suggest that the total S concentration in pine needles is a better indicator of SO2 changes in the ambient air, while that in Hypogymnia physodes seems to be a better bioindicator of total S deposition, past and present.  相似文献   

13.
Needles of Scots pine (Pinus sylvestris L.) from 25 and 40 sampling plots in southern and northern Finland, respectively, that had earlier been analysed for total sulphur concentration (St) were reanalysed for foliar sulphate sulphur (SO4–S) and total nitrogen (Nt). Organic sulphur content (So) was calculated as the difference between St and SO4–S. Current (c) and previous-year (c+1) needles were collected from southern Finland in December 1989 and c – c+2 needles from northern Finland in September-October 1990/September 1992. The results show that the St concentration and St/Nt ratio in Scots pine needles are good indices of dry deposition of SO2 in general, while SO4–S concentrations and SO4–S/So ratios can be used in areas with low N supply from the soil and/or low wet deposition of N. The normal St concentration in needles of Scots pines growing on a podzol with low N supply is considered to be 500–700 μg g-1 and that of SO4–S 100–200 μg g-1. An increase of 100 μg g-1 in needle St may be attributed to a rise of 1.4 μg m-3 in ambient SO2 concentration in areas with relatively low SO2 concentrations (>15 μg m-3). A critical level of 5 μg m-3 as an annual and growing season mean is proposed for forestry in northern Europe (north of 60°N).  相似文献   

14.
Plant secondary compounds have an important role in defense responses against herbivores and pathogens. This study summarises published and some unpublished data from a series of fumigation experiments where Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) seedlings were exposed to different concentrations of gaseous air pollutants, ozone (O3), sulphur dioxide (SO2) or nitrogen dioxide (NO2), in growth chambers. Concentrations of monoterpenes, resin acids and total phenolics were studied. Overall, needle monoterpenes were not affected by pollutants. Only very high level of O3 (600 ppb) decreased concentration of some individual monoterpenes in pine needles. O3 did not have effect on concentrations of resin acids in pine needles. In contrast, the concentration of some individual resin acids increased in O3-exposed pine shoots and in O3-exposed needles of one spruce clone. The highest dose of SO2 decreased concentrations of resin acids in pine needles, but low exposure levels did not have effects. However, SO2 had no effects on the resin acids concentrations of spruce needles, except some minor individual compounds were affected in clonal spruces. Increased concentrations of resin acids was found in pine shoots exposed to NO2. Total phenolics of needles were not affected by pollutants. These observations suggest that among secondary compounds there is variation in sensitivity to air pollutants and genetically different trees have different responses to air pollutants.  相似文献   

15.
Humus changes after introduction of beech and oak into Scots‐pine monocultures Medium‐ and long‐term (16 to 83 years) effects of an introduction of broadleaf‐tree species (Common beech [Fagus sylvatica] and European‐Sessile Oak [Quercus robur/petraea]) into mature Scots‐pine (Pinus sylvestris) stands on humus type and chemical properties of the Oh layer (pH value, base saturation, C : N ratio) were studied on 16 sites in Bavaria/Germany. The sites investigated covered a large range with respect to elevation, climate, parent material, and soil type. At most sites, the introduction of beech resulted in a significant change of the soil humus type from biologically inactive humus types to more active ones. The strongest changes occurred on the poorest sites, where forest floors under pure pine were particularly biologically inactive. In most cases, the changes in humus type were accompanied by significant increases in the pH value and the base saturation and significant decreases in the C : N ratio of the Oh layer. However, the latter effect was not noticed at most sites with initial C : N ratios higher than 30. In contrast to beech, the introduction of oak did not result in a systematic change of the humus type, the pH value, or the base saturation of the Oh layer. In spite of the considerable change of humus type under beech to biologically more active types, the introduction of broadleaf trees did not result in a systematic change of the thickness or the mass of the forest floor. A decrease in the mass of the Of layer was compensated by an increase of the Oh‐layer mass. All studied sites considered, the introduction of broadleaf trees into Scots‐pine monocultures resulted on average in an 8% decrease of the total amount of organic carbon (Corg) in the forest floor; the Corg amount in the uppermost 10 cm mineral soil increased by 9%. At 35% of all investigated sites, broadleaf tree introduction resulted in increased (+5% to +18%) topsoil (forest floor and uppermost 10 cm mineral soil) Corg stocks. At 30% of the sites, the stock changes were less than ±5%, and on 35% of all sites, soil Corg stocks decreased by –5% to –36%. The average change in the topsoil Corg stock for all studied sites was –5%. The introduction of beech into Scots‐pine monocultures resulted in an ecologically desired translocation of soil organic matter from the forest floor into the mineral topsoil. It is an effective and sustainable silvicultural measure to restore and revitalize acidified, nutrient‐depleted topsoils with biologically inactive humus types.  相似文献   

16.
Ectomycorrhizas are an integral, functioning part of many conifer tree species root systems and often considered a link in the causal chain leading to forest decline. In our experiment 12-year-old Scots pine trees grown for 10 years on a polluted acid soil with high aluminium content were compared to a control stand in western Poland. Soil at the polluted site had lower pH than the control site, increased aluminium availability and very low microbial activity. Roots analysed over two years showed lower number of mycorrhizal tips at the polluted site, but only when calculated per soil volume. Differences between sites were not significant when number of mycorrhizal tips was expressed per root mass. There was no significant reduction in the occurrence of any mycorrhizal morphotype. The number of mycorrhizas on trees from the polluted stand was negatively correlated with aluminium content in the needles. Our results showed no clear pollution effect on mycorrhizas in a young stand of Scots pine.  相似文献   

17.
Tannins are polyphenolic compounds that may influence litter decomposition, humus formation, nutrient (especially N) cycling and ultimately, plant nutrition and growth. The aim of this study was to determine the response of C and N transformations in soil to tannins of different molecular weight from Norway spruce (Picea abies (L.) Karst) and Scots pine (Pinus sylvestris L.) needles, tannic acid and cellulose. Arginine was added to test whether the soil microbial community was limited by the amount of N, and arginine+tannin treatments were used to test whether the effects of tannins could be counteracted by adding N. Soil and needle samples were taken from adjacent 70-year-old Scots pine and Norway spruce stands located in Kivalo, northern Finland. Tannins were extracted from needles and fractioned based on molecular weight; the fractions were then characterized by LC-MS and GC-MS. Light fractions contained tannin monomers and dimers as well as many other compounds, whereas heavy fractions consisted predominantly of polymerized condensed tannins. Spruce needles contained more procyanidin than prodelphinidin units, while in pine needles prodelphinidin units seemed to be dominant. The fractions were added to soil samples, pine fractions to pine soil and spruce fractions to spruce soil, and incubated at 14 °C for 6 weeks. CO2 evolution was followed throughout the experiment, and the rates of net mineralization of N and net nitrification, concentration of dissolved organic N (DON) and amounts of microbial biomass C and N were measured at the end of the experiment. The main effects of the fractions were similar in both soils. Light fractions strongly enhanced respiration and decreased net N mineralization, indicating higher immobilization of N in the microbial biomass. On the contrary, heavy fractions reduced respiration and slightly increased net N mineralization, suggesting toxic or protein-precipitating effects. The effects of tannic acid and cellulose resembled those of light fractions. DON concentrations generally decreased during incubation and were lower with heavy fractions than with light fractions. No clear differences were detected between the effects of light and heavy fractions on microbial biomass C and N. Treatments that included addition of arginine generally showed trends similar to treatments without it, although some differences between light and heavy fractions became more obvious with arginine than without it. Overall, light fractions seemed to act as a labile source of C for microbes, while heavy fractions were inhibitors.  相似文献   

18.
The effect of heavy metal and gaseous pollution on genetic make up due to selection and mortality was studied in eight European Scots pine (Pinus sylvestris L.) populations. Genetic structure of these populations was evaluated after 13 years of growth at two sites, one located in the vicinity of a copper smelter in Glogow (southern Poland) and another in a control area (Kornik, central Poland). Based on data from 10 enzymatic loci, studied by starch gel electrophoresis, the following genetic parameters were characterized: mean number of alleles and genotypes per locus, heterozygosity and genotype polymorphism index, genetic diversity among sites and genetic similarity according to Nei and Roychoudhury. Most of the parameters differed both between sites as well as between pairs of populations. Mean multilocus observed heterozygosity and genotype polymorphism indices were 8% and 6% lower respectively at the control site than in the polluted one. Populations from the site polluted by heavy metals demonstrate higher genetic diversity then those from the control. Genetic similarities showed differentiation of particular populations from both locations in response to industrial pollution. These results provide evidence that the general pattern of adaptation strategy of populations to pollution stress is connected with increasing genetic variation. The best isoenzymatic markers for monitoring changes in the genetic structure of Scots pine populations under the influence of industrial pollution are fluorescent esterase (FEST), glutamic-oxaloacetatic transaminase (GOT-A and GOT-B), alcohol dehydrogenase (ADH), malate dehydrogenase (MDH-A) and shikimate dehydrogenase (ShDH-A) loci.  相似文献   

19.
The accumulation of salt and visibleinjuries on Scots pine needles (Pinus sylvestris) were investigated in a field study duringtwo years 1992–1994. Two sampling plots 4 km apart alongthe highway 9 in eastern Finland were selected. AtSavo-Karjala region, the use of road salt was reducedto about one tenth from normal (slightly salted site),whereas, the use of road salt continued normally atthe Central Finland region (heavily salted site).Current, one-year and two-year-old needles weresampled eight times during years 1992–1994. Visibleinjuries in the pine needles were recorded and sodium,chloride and calcium concentrations analysed. Duringthe two-year study, reduced use of deicing saltclearly reduced the accumulation of salt components,sodium and chloride, and induction of visible injuriesin the pine needles growing closest to the roadside.No changes in needle calcium concentrations wereobserved. In the sampling plot along the heavilysalted site, browning and premature needle loss wasdetected especially during late spring. Deleteriouseffects of road salt did not reach far from the road,since at distances of 20 to 30 m, the saltconcentrations and visible injuries in needles wereinsignificant. Since no changes in soil saltconcentrations between sites were observed, aerialsalt spray is considered more important to saltaccumulation in needles than root uptake. The changesin weather conditions have a significant effect on theaccumulation of salt in needles and occurrence of thevisible injuries. Great fluctuations in temperatureand salt use during winter exacerbate the needleinjuries. Thus, the salt concentrations and visibleinjuries caused by such concentrations of salt shouldalways be considered with respect to the climatic conditions.  相似文献   

20.
保水剂和微生物菌肥对半干旱区造林和土壤改良的影响   总被引：7，自引：3，他引：4  
试验分别设置低、中、高浓度保水剂(20,40,60g/株)和微生物菌肥(150,300,450g/株)用于张北半干旱区风沙土樟子松造林。通过分析不同处理对土壤田间持水量、有效水分含量、水稳性团聚体含量、微生物菌落数量和微生物量碳、氮等指标的差异,研究保水剂与微生物菌肥对土壤物理性质、土壤微生物以及樟子松成活率的影响,探究适用于干旱、半干旱区樟子松造林的最佳配比。结果表明:保水剂和微生物菌肥能够显著改良土壤,提高造林成活率,但不同浓度配比对各项指标影响效果不同。高浓度保水剂单施对田间持水量,有效水分含量和水稳性团聚体含量提高最明显,分别较对照组提高了141%,150%,63.8%;中浓度保水剂和高、中浓度菌肥混施显著提高了土壤微生物活性和土壤微生物量,其中真菌,细菌和放线菌分别较对照组高77%,108%,93%,微生物碳、氮分别较对照组增加132%,178%。此外,施加保水剂和微生物菌肥对樟子松生长具有显著促进作用,株高、地径平均值分别较对照组提高6%,12%。保水剂提高樟子松成活率的效果优于其与微生物菌肥混施,且中浓度保水剂条件下造林成活率最高。在干旱、半干旱区造林时,采用中浓度保水剂和微生物菌肥配施可以改良土壤,提高造林成活率。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号