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 0 毫秒
1.
Macronutrients (P, S, K, Na, Mg, Ca), heavy metals (Fe, Zn, Mn, Cu, Pb, Cr, Ni, Cd,) and Al concentrations as well as values of Ca/Al in the tip, middle and base sections, and sheaths of current year and previous year needles of Pinus massoniana from Xiqiao Mountain were analyzed and the distribution patterns of those elements were compared. The results indicated that many elements were unevenly distributed among the different components of needles. Possible deficiency of P, K, Ca, Mn and Al toxicity occurred in needles under air pollution. Heavy metals may threaten the health of Masson pine. Needle sheaths were good places to look for particulate pollutants, in this case including Fe, Cu, Zn, Pb, Cr, Cd and Al.  相似文献   

2.
范荣桂  戴艺  董雪  陈瑶 《环境工程学报》2016,10(7):3701-3706
以马尾松松针为吸附剂,研究其对水中磺胺二甲基嘧啶的吸附特性。考察了磺胺二甲基嘧啶的初始浓度为10 mg·L-1、温度为25 ℃时松针吸附剂饱和吸附量及饱和吸附时间,分析了温度、pH值对其吸附能力的影响,研究了吸附过程的动力学和热力学特点,并进行了相应的分析和计算。实验结果表明,在实验条件下,松针对磺胺二甲基嘧啶的吸附在 35 min达到饱和,其饱和吸附量为 0.229 mg·g-1。经准一级动力学方程拟合出的 qe为 0.24 mg·g-1与实验所得值0.229 mg·g-1接近,且相关系数R2=0.998 1,说明准一级动力学模型能较好地描述松针对磺胺二甲基嘧啶的吸附行为,且满足Langmuir 等温吸附模型。分析表明,松针对磺胺二甲基嘧啶的吸附行为为单分子层的自发吸附,且以物理吸附为主。  相似文献   

3.
Fifteen or 18-month-old Aleppo pine seedlings were fumigated with different concentrations and doses of ozone over a period of 2-16 days in controlled-environmental growth chambers. The total fatty acid content and ultrastructure of the current year needles were subsequently analysed. In acute, high concentration exposures, significant reductions in the levels of linolenic acid were detected. Increases in myristic or palmitic acid were common in needles exposed to lower concentrations of ozone. Ultrastructural studies revealed reductions in chloroplast size and a darkening of stroma at low ozone exposures while at high concentrations disruption of the chloroplast membranes was also identified.  相似文献   

4.
Maps of the distribution of environmental pollution by sulfur (S), zinc (Zn), cadmium (Cd), lead (Pb), copper (Cu), and arsenic (As) for the territory of Poland and the Warsaw (Warszawa) district were developed on the basis of chemical analysis of Scots pine (Pinus sylvestris L.) needles collected from randomly selected sampling points during 1983-1985. The maps show deposition zones for the studied elements and can help in identification of sources and directions of air pollution dispersion. This study indicated that vegetation in Poland is greatly endangered by sulfur dioxide (SO(2)) and other sulfurous air pollutants, whereas Zn, Cd, Pb, and As do not pose an immediate threat to vegetation in most of the country's territory. However, in the urban-industrial agglomeration of Katowice-Cracow, very high pollution with Z, Cd, Pb and As could limit growth and development of some sensitive plant species. Higher than normal levels of As in some areas of Poland (Upper Silesia, Glogow-Lubin Copper Region, and areas close to the Russian border near Braniewo) might affect the health of humans and animals. Results of this study indicated that Poland's environment was not contaminated with Cu.  相似文献   

5.
6.
Needles of 20-year-old Scots pine (Pinus sylvestris L.) saplings were studied in an ultraviolet (UV) exclusion field experiment (from 2000 to 2002) in northern Finland (67 °N). The chambers held filters that excluded both UV-B and UV-A, excluded UV-B only, transmitted all UV (control), or lacked filters (ambient). UV-B/UV-A exclusion decreased nitrate reductase (NR) activity of 1-year-old needles of Scots pines compared to the controls. The proportion of free amino acids varied in the range 1.08-1.94% of total proteins, and was significantly higher in needles of saplings grown under UV-B/UV-A exclusion compared to the controls or UV-B exclusion. NR activity correlated with air temperature, indicating a “chamber effect”. The study showed that both UV irradiance and increasing temperature are significant modulators of nitrogen (N) metabolism in Scots pine needles.  相似文献   

7.
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.  相似文献   

8.
The effects of simulated acid rain on the phyllosphere microflora of pine (Pinus sylvestris L.) were studied experimentally in northern Finland during the summer of 1988. Trees were irrigated with artificial acid rain of pH4 and pH3 (H(2)SO(4) and HNO(3), weight ratio of S:N=2.86:1). Untreated trees and trees irrigated with spring water (pH6) were used as controls. Two sampling heights (0.5m and 2m) were used. The needles were colonized exclusively by epiphytic fungi, mainly Aureobasidium pullulans (de Bary) Arnaud. The lower branches had significantly more epiphytic fungi than the upper branches. Compared to the control trees, the numbers of epiphytic fungi were significantly decreased on the needles of trees irrigated with acid rain. Acid rain affected the number of epiphytic fungi equally at both sampling heights. The species composition of the epiphytic fungi was not affected by the acid treatments.  相似文献   

9.
Three-year-old clonal spruce trees, kept in growth chambers, were treated with ozone and acid mist during a period of 14 months. One half of the trees were grown on an acidic sandy soil, the other half on a calcareous soil rich in carbonate. At the end of the fumigation period, carbohydrates (glucose, fructose, sucrose, raffinose, starch, glucose-1-phosphate and fructose-6-phosphate) and parameters of the energy status (ATP-, AdN-(ATP + ADP + AMP)- levels, ATP/ADP-ratios and adenylate-energy-charge-(AEC)-values) were determined in the current-year's needles. The results indicate that the metabolic status of a plant tissue is not only influenced by the nature of the air pollutants. Soil factors play an important role in metabolic changes within the plant and are thus of relevance in the manifestation of damage symptoms.  相似文献   

10.
This work analyses the spatial distribution, the origin, and the shale-normalised fractionation patterns of the rare earth elements (REE) in the alluvial aquifer of the Guadiamar River (south-western Spain). This river received notoriety in April 1998 for a spill that spread a great amount of slurry (mainly pyrites) and acid waters in a narrow strip along the river course. Groundwaters and surface waters were sampled to analyse, among other elements, the REEs. Their spatial distribution shows a peak close to the mining region, in an area with low values of pH and high concentrations of sulphates and other metals such as Zn, Cu, Co, Ni, Pb, and Cd. The patterns of shale-normalised fractionation at the most-contaminated points show an enrichment in the middle rare earth elements (MREE) with respect to the light (LREE) and heavy (HREE) ones, typical of acid waters. The Ce-anomaly becomes more negative as pH increases, due to the preferential fractionation of Ce in oxyhydroxides of Fe.  相似文献   

11.
Ozone (O(3)) flux into Norway spruce (Picea abies) and cembran pine (Pinus cembra) needles was estimated under ambient conditions at six rural sites between 580 and 1950 m a.s.l. We also assessed age-related differences in O(3) flux by examining changes in leaf conductance across the life span of Norway spruce. At the leaf level O(3) flux into the needles was effectively controlled by stomatal conductance and, hence by factors such as temperature, irradiance and humidity, which control stomatal conductance. Seasonal variations in O(3) flux were mainly attributed to the course of the prevailing temperature. During the growing season, however, data have emphasised leaf-air vapour pressure difference as the environmental factor most likely to control stomatal conductance and O(3) flux into the needles. In the sun crown stomatal conductance averaged over the growing season decreased with increasing tree age from 42.0+/-3.5 mmol O(3) m(-2) s(-1) in 17-year-old trees to 7.1+/-1.0 mmol O(3) m(-2) s(-1) in 216-year-old trees, indicating that O(3) concentration in the substomatal cavities is higher in young than in old trees. Independent from tree age stomatal conductance and O(3) flux were approximately 50% lower in shade needles as compared to sun-exposed needles. Stomatal conductance was also greater in the current flush (24+/-5.6 mmol O(3) m(-2) s(-1)) and in 1-year old needles (16+/-4 mmol O(3) m(-2) s(-1)) than in older needle age classes (12+/-1 mmol O(3) m(-2) s(-1), averaged across the four older needle age classes). In trees similar in age (60-65 years old) average O(3) flux into sun needles increased from 0.55+/-0.36 nmol m(-2) s(-1) at the valley floor to 0.9 nmol m(-2) s(-1) in 1950 m a.s.l. Cumulative O(3) uptake during the vegetation period increased from 11.4+/-1.7 mol m(-2) in the valley to 14 mol m(-2) at the alpine timberline. Although stomatal conductance provides the principal limiting factor for O(3) flux, additional field research is necessary in order to improve our understanding concerning the quantitative 'physiological threshold dose' which internally can be active and can have adverse effects of O(3) on forest trees.  相似文献   

12.
Polycyclic aromatic hydrocarbons (PAHs) have been widely studied with respect to their carcinogenic and mutagenic effects on animals and human cells. Phenanthrene (PHE) and fluoranthene (FLU) effects on the needle photosynthetic traits of 2-year-old Japanese red pine (Pinus densiflora Sieb. et. Zucc.) seedlings were investigated. Three months after fumigation of foliage with solutions containing these PAHs (10 microM each), FLU had negative effects on net photosynthesis at near-saturating irradiance, stomatal conductance, initial chlorophyll fluorescence, and the contents of total chlorophyll, magnesium, and ribulose 1,5-bisphosphate carboxylase (rubisco) of current-year needles. PHE had similar negative effects to FLU but in lesser magnitude. The effects of the PAHs were mitigated by the addition of an OH-radical scavenger (mannitol) into the PAH solutions. PAHs deposited on the surface of pine needles may induce the generation of reactive oxygen species in the photosynthetic apparatus, a manner closely resembling the action of the herbicide paraquat.  相似文献   

13.
Twenty-nine conifer needles in mountain-valley areas from the southeastern Tibet were collected with altitude span from 1520 to 4340m above sea level (m.a.s.l.). They were analyzed for organochlorine pesticides (OCPs), including hexachlorocyclohexanes (alpha-, beta-, gamma- and delta-HCH), dichlorodiphenyltrichloroethane (p,p'-DDE, p,p'-DDD, o,p'-DDT and p,p'-DDT) and hexachlorobenzene (HCB). Concentrations of OCPs in samples ranged from 0.69 to 4.3 ng/g, from 0.39 to 4.9 ng/g and from 1.9 to 20.5 ng/g (dry weight) for HCB, total HCHs and DDTs, respectively. The levels of DDTs found here were noticeably higher than those from other high mountainous regions. Composition of HCH isomers and DDTs was analyzed, and it was found that the high ratio of o,p'-DDT/p,p'-DDT might be caused by the application of dicofol in adjacent regions. A number of environmental factors controlling the distribution of OCPs in regional scale were also discussed in this paper.  相似文献   

14.
In the present field study the role of ascorbate in scavenging the harmful atmospheric trace gases O3 and NO2 was examined. For this purpose ascorbate contents were determined in needles of adult Scots pine trees (Pinus sylvestris L.) during three consecutive years. Ascorbate contents were correlated with ambient tropospheric O3 and NO2 concentrations and with meteorological parameters. The results showed a strong correlation of atmospheric O3 but not of atmospheric NO2 concentrations with the apoplastic content of ascorbate during the seasonal course. Ascorbate contents in needle extracts did not correlate with ambient trace gas concentrations. In the apoplastic space, but not in needle extracts ascorbate contents correlate highly significantly with global radiation. From these results it is assumed that apoplastic ascorbate in Scots pine needles is adapted to the actual atmospheric O3 concentration to mediate immediate detoxification of O3, while the atmospheric O3 concentration itself is largely dependent on light intensity.  相似文献   

15.
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.  相似文献   

16.
Levels of selected organochlorine compounds in pine needles were measured in two sampling series. The first series collected in 1989 covered Southern Germany to Northern Scandinavia, and the second collected in 1990 covered Czechoslovakia to Estonia. The levels of alpha-hexachlorocyclohexane (alpha-HCH) and hexachlorobenzene (HCB) were relatively uniform throughout Europe, while the levels of gamma-hexachlorocyclohexane (gamma-HCH) and the DDT group show higher levels in the southern parts of the investigated area. The deposition patterns of all compounds except alpha-HCH indicate a dependence on fresh release from diffuse or point sources rather than global fractionation. The analytes accumulate in the needles until senescence starts and, generally, the oldest needles have the highest concentrations. The accumulation rate of the analytes in mountain pine needles is about half that of Scots pine needles indicating the importance of species differences.  相似文献   

17.
Mature grafts of five Sitka spruce (Picea sitchensis (Bong.) Carr.) clones were exposed to simulated acid mist comprising an equimolar mixture of H(2)SO(4) and NH(4)NO(3) (1.6 and 0.01 mol m(-3)) at pH 2.5 and 5.0. Mist was applied to potted plants growing in open-top chambers on consecutive days, four times a week, at a precipitation equivalent of 1 mm per day. The total exposure to polluted mist was equivalent to three times that measured at an upland forest in SE Scotland. The aim of the experiment was to characterize the response of juvenile foliage produced by physiologically mature grafts (on seedling root stock) and compare it with the behaviour of juvenile foliage on seedlings. Development of visible foliar damage was followed through the growing season. Measurements of needle length, diameter, weight, surface area, surface was weight and wettability were made on current year needles to determine whether particular foliar characteristics increased susceptibility to injury. Significant amounts (> 10%) of visible needle damage was observed on only one of the five clones. Damage was most severe on the clone with the most horizontal branch and needle habit, but over the five clones there was no relationship between angle of branch display and damage. Likewise no combination of needle characteristics (length, width, area, amount of wax) was indicative of potential susceptibility. A comparison with previous acid misting experiments using seedlings suggests that juvenile foliage on physiologically mature trees is equally susceptible to visible injury as juvenile seedling foliage. Data of budburst differed among clones, and in this experiment exerted the over-riding influence on development of injury symptoms. Foliage exposed to a combination of strong acidity and high sulphate concentrations over the few weeks immediately following budburst suffered most visible injury. The absence of significant amounts of visible damage in UK forests probably reflects the general low susceptibility to visible injury of Sitka spruce exposed to acid mist.  相似文献   

18.
Kong FX  Liu Y  Hu W  Shen PP  Zhou CL  Wang LS 《Chemosphere》2000,40(3):311-318
Biochemical responses of Pinus massoniana, with and without the inoculation mycorrhizal fungus Pisolithus tinctorius at the root, to artificial acid rain (pH 2.0) and various Ca/Al ratios were investigated. Some enzymes associated with the nutritive metabolism, such as acid phosphatase, alkaline phosphatase, nitrate reductase, mannitol dehydrogenase and trehalase, in the roots, stems and leaves of plant were obviously inhibited by the artificial acid rain and Al. After treatment with pH 2.0 + Ca/Al (0/1 or 1/10) artificial acid rain, the protein content in the organs was decreased. However, the activities of superoxide dismutase (SOD) and peroxidase (POD) and glutathione (GSH) concentrations were induced. It demonstrated that acid rain and Al could induce oxygen radicals in plant. Compared with the treatments with lower pH or Al, respectively, the combination of lower pH and Al concentration was more toxic to P. massoniana. Al toxicity could be ameliorated by the addition of Ca and the amelioration was the most when the ratio was 1/1 among the various Ca/Al ratio. Infection with mycorrhizal fungus P. tinctorius at the root of P. massoniana increased the ability of the plant to resist the toxicity of artificial acid rain and Al stress.  相似文献   

19.
Forest declines in Europe and the northeastern United States are widely believed to be associated with deposition of air pollutants, perhaps including nitric acid vapor. The experiments presented here, which were conducted in indoor chambers, involved measurement of steady-state rates of nitric acid deposition on foliage of seedlings of eastern white pine. Nitric acid concentrations ranged from 37 to 1260 ppb, but were mostly in the 130-180 ppb range. Between 130 and 180 ppb, much of the deposited nitric acid could be removed by washing leaf surfaces with water. Amounts of nitrate removed by washing increased with exposure duration to a maximum of 7.6 nmol cm(-2) after about 8 h. Although nitrate concentrations in the washings remained constant after 8 h, nitric acid deposition nonetheless continued at a steady-state rate. We have termed this steady-state deposition 'trans-cuticular' on the assumption that the nitric acid diffuses through the cuticle. Resistance to trans-cuticular uptake (69 m(2) s mol(-1)) far exceeded resistance to diffusion across the unstirred layer at the surface of the leaf (5 m(2) s mol(-1)). High concentrations used in these experiments preclude quantitative extrapolation to ambient conditions; however, we have demonstrated that the white pine cuticle is both a major storage pool and a major barrier to uptake of deposited nitric acid.  相似文献   

20.
A long-term experiment was performed to study the effects of O3 and drought-stress (DS) on Aleppo pine seedlings (Pinus halepensis Mill.) exposed in open-top chambers. Ozone reduced gas exchange rates, ribulose-1,5-biphosphate carboxylase/oxygenase activity (Rubisco), aboveground C and needle N concentrations and C/N ratio and Ca concentrations of the twigs under 3 mm (twigs<3) and the aerial biomass. Also it increased phosphoenolpyruvate carboxylase (PEPc) and N and K concentrations of the twigs<3. Water stress decreased gas exchange rates, predawn needle water potential (PsiPd), C/N ratio, twigs<3 Ca, plant growth, aerial biomass and increased N, twigs with a diameter above 3 mm P and Mg concentrations. The combined exposure to both stresses increased N concentrations of twigs<3 and roots and aboveground biomass K content and decreased root C, maximum daily assimilation rate and instantaneous water use efficiency. The sensitivity of Aleppo pine to both stresses is determined by plant internal resource allocation and compensation mechanisms to cope with stress.  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