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 15 毫秒
1.
An area in Lithuania containing coniferous stands of Scots pine and Norway spruce that were dead or damaged due to nitrogen pollution by a nitrogen fertilizer plant (JV Achema) was found to have expanded between 1974 and 1989 to a distance of 20 to 25 km northeast of the plant in the direction of prevailing winds. Over the last 10 years, when nitrogen pollution by the plant had decreased, a clear process of recovery of the damaged ecosystems could be observed. The following features of this process as it occurred in damaged Scots pine stands are discussed: (1) refoliation (or decreased defoliation) of damaged trees, where a clear positive trend could be observed; (2) changes in the species composition and in the covering by ground vegetation, where small changes and indication of less-nitrophilous species coverage could be detected; and (3) chemical and acidity changes in Luvisols and Arenosols, where a significant decrease could be seen especially concerning nitrate concentrations.  相似文献   

2.
本文讨论环境污染对植物伤害的症状、植物抗污性标准、环境监测植物的优点和选择指标。在此基础上,筛选出福建三明地区环保植物资源的种类,并推荐适用于当地不同环境特点和功能的环保植物。  相似文献   

3.
Landsat TM images were obtained of blight damage to a Japanese red pine forest in the western part of Hiroshima Prefecture, Japan, using a spectral vegetation index; that is, the ratio of the digital number (relative reflectance on the ground surface) of TM Band 4 to Band 3 observed in May 1987, which decreased with the increase in the canopy cover of damaged pine trees measured in the field. The TM images suggested that the areas of damaged forest were concentrated in or near cities, industrial areas and expressways. The correlation between forest damage and environmental factors (air pollution and urban development) around the pine forest was therefore analysed by overlaying the blight damage with the proportion of developed areas obtained from TM data or mesh data of air pollution. The results of analysis indicated a significant correlation between forest damage and environmental factors, and showed that these two environmental factors made nearly equal contributions to the blight damage in the pine forest. This suggests that urban development and air pollution may affect the physiology of pine trees and promote blight by reducing the resistance of trees to the pinewood nematode.  相似文献   

4.
广州地区酸雨对植物的影响及损失估算   总被引:5,自引:1,他引:5  
胡迪琴  苏行 《生态科学》1999,18(1):24-29
综合分析了广州地区酸雨污染对植物的影响,并根据有关植物生态基准值,估算酸沉降影响农作物、森林的损失.结果表明,酸雨对广州地区植物生态环境已造成较大的危害,应引起重视  相似文献   

5.
The aim of this research is to investigate changes in the annual radial increment of Scots pine (Pinus sylvestris L.) in the vicinity of intensive (3–10 km) and moderate (11–20 km) industrial pollution during different growth periods (growth promotion, inhibition, and recovery). Low level of emission was beneficial for tree growth during the growth promotion period, and the annual radial increment in the zones of intensive and moderate pollution increased by approximately 15–25% and 10%, respectively. Severe loss was reported to forests during the growth inhibition period when nitrogen and sulphur dioxide emissions were 37–40 thousand (thou.) tons per year. About 40–45% tree radial increment loss was observed in the stands closest to the pollution source, and 15–20% loss was observed for the most distant stands. The stabilization of radial growth decrease and the beginning of recovery of damaged stands began in 1988–1992, when the annual amount of industrial emissions and environmental pollution were considerably reduced. The stabilization of radial growth and the initiation of recovery after pollution reduction were high for the most damaged stands. Their radial increment was stable and close to that of the control stands in 2000–2011. Stands with less damage growing further from the pollution source were recovered earlier, and their radial increment stabilized near the control increment in 1995–1999. The results of linear regression analysis demonstrated that the impact of pollution is different for stands growing at different distances from the plant, and the impact decreases with distance (R2 = 0.78 and R2 = 0.75, respectively; p < 0.05).  相似文献   

6.
Repair of bulky DNA lesions deriving from polycyclic aromatic hydrocarbons   总被引:1,自引:0,他引:1  
Genomic DNA is damaged by a variety of factors exerting an adverse effect on human health, such as environmental pollution, UV light, ionizing radiation, and toxic compounds. Air pollution with products of incomplete combustion of hydrocarbon fuels and wastes of various industries are main sources of polycyclic aromatic hydrocarbons, whose metabolites can damage DNA by forming bulky DNA adducts, which potentially lead to mutations and cancer. Nucleotide excision repair is the main pathway that eliminates these lesions in eukaryotic cells. The excision efficiency of bulky adducts depends on many factors, including the structure of a bulky substituent and the degree of DNA double helix distortion induced by a lesion. Clustered DNA lesions are the most dangerous for the cell. Several DNA repair systems cooperate to recognize and remove such lesions. The review focuses on the mechanisms that repair DNA with single and clustered bulky lesions, taking the natural carcinogen benzo[a]pyrene as an example.  相似文献   

7.
厦门海湾生态系统退化的影响因素及生态修复意义   总被引:4,自引:0,他引:4  
以厦门海湾生态服务功能逆向演变的历史过程为例,对该区域生态系统服务功能退化主要影响因素进行了分析。结果表明,不适当的围堤填海,过度的海洋资源开发,污染防治工程措施滞后于快速发展的区域开发,是造成海湾生态服务功能下降的重要原因。本文通过受损生态系统在长期的生态恢复过程中所付出的代价,证明生态系统资源的经济价值,进一步认识到人与环境协调发展的重要性。  相似文献   

8.
The three youngest age-classes of needles of Norway spruce ( Picea abies ) were collected from four sites in the Krusne Hory Mountains (Czech Republic) characterized by different levels of damage caused by environmental pollution. Histochemical methods did not reveal any differences in localization of phenolics among the needles. Mesophyll cells close to the epidermis of needles and cells around resin ducts and substomatal cavities often accumulated higher amounts of phenolics than the rest of the mesophyll cells, but this was independent of age and damage. Needles of different age- and damage-class did not show any marked changes in general lignification pattern. However, a lower intensity of histochemical detection of lignin was observed in needles from the most damaged site. This finding was confirmed by chemical analysis using thioglycolic acid. Generally, the amount of lignin in mesophyll cells was lower in damaged trees than in healthy ones. Using the Folin–Ciocalteau method, no significant differences in the total content of phenolics were observed in the needles, although HPLC revealed marked alterations in the forms of seven phenolic acids. Concentrations of conjugated forms of phenolic acids (esters and glycosides) were higher in damaged needles (255.9 μg g−1 f. wt) than in healthy needles (189.8 μg g−1 f. wt). By contrast, content of esterified phenolic acids incorporated into cell walls was higher in needles from healthy trees (101.1 μg g−1 f. wt) than in damaged needles (78.3 μg g−1 f. wt). Marked differences were also observed in the activity of soluble peroxidases, although the activity of ionically bound forms was approximately the same in healthy and damaged needles. The total amounts of chlorophylls and carotenoids decreased as environmental damage increased.  相似文献   

9.
Forest dieback in Czechoslovakia   总被引:1,自引:0,他引:1  
The article reviews the literature dealing with levels of air pollution in Central Europe and Czechoslovakia particulary in connection with the rate of forest damage and dieback since the fifties. To date 57 percent of forests on an area of 15.000 square km are damaged in Czech republic and more than 40.000 ha of dead Norway spruce forest had to be cut out. Deforested hills are vegetated mostly by Calamagrostis villosa only. The reforestation faces many obstacles of which the change of mezoclimate, the acidification and intoxication of the soil, the disappearance of mycorrhizal fungi and pressure of consumers may be named.  相似文献   

10.
用蚯蚓溶酶体作为检测土壤污染的生物标志物   总被引:4,自引:0,他引:4  
蚯蚓体腔细胞内的溶酶体能积累中性红染料.当受到环境胁迫时,溶酶体膜容易破裂,染料就逐步泄露到细胞质中,使细胞染成红色.中性红的保持时间(neutral red retention time,NRRT)可反映溶酶体受损情况.用不同浓度乙草胺和不同浓度Se处理赤子爱胜蚓(Eisenia fetida),观察体腔细胞溶酶体中性红染色的保持时间.结果表明,随乙草胺和Se处理浓度的增高和处理时间的延长,NRRT缩短;NRRT与土壤中乙草胺残留的浓度呈明显的负相关,与蚯蚓体内富集的Se也有明显的负相关.可见,蚯蚓溶酶体中性红染色保持时间是测定土壤污染物的生物标志物,在环境风险评价和土壤监测中具有稳定性和准确性,可作为早期预警生物标志物.  相似文献   

11.
【目的】松花江流域是中国最早的工业基地之一,其水生态环境遭到严重破坏,环境保护工作面临巨大挑战。开展松花江流域水质评价及典型生物类群多样性状况调查,可为松花江流域生态系统的保护和修复提供依据。【方法】于2016年7月调查整个松花江流域近岸的大型底栖动物群落组成和测定水质理化指标,开展其水质理化特征评价和生物指数评价,并探讨底栖动物群落分布与水环境因子间的关系。【结果】理化指标评价结果显示,南源松花江水质状况最差,处于中度污染;北源松花江处于轻度污染;梧桐河水质最好,处于良好状态。松花江流域3个河段的底栖动物群落结构存在空间差异性。另外,梧桐河的物种多样性最高,北源松花江次之,南源松花江最低。溶解氧和营养元素K的浓度是驱动底栖动物群落组成发生显著性差异的主要环境因子。生物指数评价结果显示,3个河段水质均处于轻度污染状态。【结论】松花江流域水质处于轻度到中度污染状态。有机污染是松花江流域面临的主要水质环境问题,对松花江流域底栖动物群落结构产生了显著影响。因此,控制有机质的输入是维持松花江流域水生态系统平衡的重要举措之一。  相似文献   

12.
流域水质管理系统构建的理论、方法和实践   总被引:6,自引:0,他引:6  
随着工农业的发展及乡村都市化 ,淡水资源的短缺成为全球性的问题。淡水资源的短缺 ,一方面是对淡水需求量增加 ,供不应求。另一方面是水体水质恶化 ,水资源退化。保护淡水资源是一项持久性的艰巨任务 ,其中水资源管理工具评价预测各种管理措施对水资源的影响 ,是必不可缺少的。工业和生活废水对水体的点源污染问题 ,早在2 0世纪 2 0年代就被意识到 ,并开展了一些水资源的保护和管理研究工作。自 192 5第一个水质数学模型Streeter Phelps[1] 用于模拟水环境中BOD和DO的动态变化研究以来 ,出现了许多水质模型并用于河流、…  相似文献   

13.
The starch content and ultrastructure of needles of Norway spruce trees [Picea abies (L.) Karst.] taken from three natural habitats, undamaged or with symptoms of novel forest decline, were investigated during the course of three years. The starch content was clearly dependent on the seasons, with a maximum in spring and a decline during summer and autumn, leading to a minimum in winter. Needles of damaged trees from one habitat exhibited in all three years from August to October a significantly higher starch content than their undamaged counterparts. Microscopic investigations of these needle samples exhibited severe damage symptoms to the phloem in macroscopically green needles, though more intensely in the needles with yellowing symptoms. The phenomenon of starch accumulation is interpreted as a delay in starch mobilization, caused by a reduction in assimilate transport capacity of the needle phloem. The lower degree of starch accumulation in needles of damaged trees from a second natural habitat corresponded well to the lesser extent of phloem damage. The difference in damage patterns are discussed in terms of the differing air pollution situations acting on both habitats.  相似文献   

14.
大型露天煤矿生态系统受损研究——以平朔露天煤矿为例   总被引:33,自引:0,他引:33  
矿区受损生态系统的恢复与重建是脆弱生态环境综合整治的重点和难点。13a的平朔露天煤矿受损生态系统定点研究表明,大型露天煤矿生态定变过程为3个阶段、4个类型。生态受损引发因子包括挖损、压占、占用和污染。生态受损特征表现为生境在100a左右的时间尺度下,以每年7800万m^3左右的岩土搬运速度,累计消失160km^2左右。而新形成的生境与原生境相比,虽沟壑消失使地貌形态趋势于简单,但重新组合堆置的固相  相似文献   

15.
Response of Soybean Seed Germination to Cadmium and Acid Rain   总被引:2,自引:0,他引:2  
Cadmium (Cd) pollution and acid rain are the main environmental issues, and they often occur in the same agricultural region. Nevertheless, up to now, little information on the combined pollution of Cd(2+) and acid rain action on crops were presented. Here, we investigated the combined effect of Cd(2+) and acid rain on the seed germination of soybean. The results indicated that the single treatment with the low level of Cd(2+) (0.18, 1.0, 3.0?mg?L(-1)) or acid rain (pH ≥3.0) could not affect the seed germination of soybean, which was resulted in the increased activities of peroxidase and catalase. The single treatment with the high concentration of Cd(2+) (>6?mg?L(-1)) or acid rain at pH?2.5 decreased the activities of peroxidase and catalase, damaged the cell membrane and then decreased the seed germination of soybean. Meanwhile, the same toxic effect was observed in the combined treatment with Cd(2+) and acid rain, and the combined treatment had more toxic effect than the single treatment with Cd(2+) or acid rain. Thus, the combined pollution of Cd(2+) and acid rain had more potential threat to the seed germination of soybean than the single pollution of Cd(2+) or acid rain.  相似文献   

16.
Oxidatively damaged DNA may be important in carcinogenesis. 8-Oxo-7,8-dihydroguanine (8-oxoGua) is an abundant and mutagenic lesion excised by oxoguanine DNA glycosylase 1 (OGG1) and measurable in urine or plasma by chromatographic methods with electrochemical or mass spectrometric detectors, reflecting the rate of damage in steady state. A common genetic OGG1 variant may affect the activity and was associated with increased levels of oxidized purines in leukocytes without apparent effect on 8-oxoGua excretion or major change in cancer risk. 8-OxoGua excretion has been associated with exposure to air pollution, toxic metals, tobacco smoke and low plasma antioxidant levels, whereas fruit and vegetable intake or dietary interventions showed no association. In rodent studies some types of feed may be source of 8-oxoGua in collected urine. Of cancer therapies, cisplatin increased 8-oxoGua excretion, whereas radiotherapy only showed such effects in experimental animals. Case-control studies found high excretion of 8-oxoGua in relation to cancer, dementia and celiac disease but not hemochromatosis, although associations could be a consequence rather than reflecting causality of disease. One prospective study found increased risk of developing lung cancer among non-smokers associated with high excretion of 8-oxoGua. Urinary excretion of 8-oxoGua is a promising biomarker of oxidatively damaged DNA.  相似文献   

17.
Peter M  Ayer F  Cudlín P  Egli S 《Mycorrhiza》2008,18(3):157-169
We investigated the ectomycorrhizal communities on the roots of adult trees and seedlings associated with three Norway spruce stands in the Czech Republic using morphological and molecular tools. The stands had different degrees of forest decline due to air pollution. The aims of the study were to obtain information about the belowground ectomycorrhizal community in a heavily damaged spruce forest and to assess whether missing ectomycorrhizal fungal partners could be one of the reasons for the observed lack of regeneration. The ectomycorrhizal species richness on the roots of adult trees was significantly lower in the heavily damaged site Mumlavska hora than in the other two, but less drastically so than that found in a fruitbody survey. The roots of adult trees and seedlings were fully mycorrhizal at this site although they were less species-rich. The most abundant ectomycorrhizal species on the root system of adult trees in all three forest stands was Tylospora fibrillosa, a member of the athelioid clade. It made up over 60% of root tips in Mumlavska hora and its proportion was at least twice that in the other two sites. This species was also an efficient colonizer of roots from seedlings, in particular, in the most damaged site. The different soil properties in this site may have caused the observed differences in the ectomycorrhizal species richness and composition. For example, cation exchange capacity and soil base saturation were lower and the soil more often saturated. However, the number of living trees and their defoliation status may well directly impact the ectomycorrhizal species composition by presumably affecting the amount of carbon delivered to the symbiotic fungal partners. Athelioids and thelephoroids are an important component of the belowground ectomycorrhizal community in most temperate and boreal forests, but the role they play might even be more crucial in stressed forest ecosystems. Based on our results, we suggest that factors other than missing ectomycorrhizal inoculum constrain natural regeneration in the heavily damaged site Mumlavska hora.  相似文献   

18.
A variety of ecological systems around the world have been damaged in recent years, either by natural factors such as invasive species, storms and global change or by direct human activities such as overfishing and water pollution. Restoration of these systems to provide ecosystem services entails significant economic benefits. Thus, choosing how and when to restore in an optimal fashion is important, but has not been well studied. Here we examine a general model where population growth can be induced or accelerated by investing in active restoration. We show that the most cost‐effective method to restore an ecosystem dictates investment until the population approaches an ‘economic restoration threshold’, a density above which the ecosystem should be left to recover naturally. Therefore, determining this threshold is a key general approach for guiding efficient restoration management, and we demonstrate how to calculate this threshold for both deterministic and stochastic ecosystems.  相似文献   

19.
巢湖流域水质生物学评价——以大型底栖动物为例   总被引:4,自引:0,他引:4  
由于长期暴露在自然环境中,底栖动物可整合不同时间尺度的物理、化学及生物信息,能反映污染物质对其造成的协同危害特征,因而被广泛应用于水体健康评价。为了弄清巢湖流域水体污染状况,于2009年4月对巢湖流域大型底栖动物进行采样调查。59个采样点中,鉴定出大型底栖动物共23种,其中:环节动物门6种,占26.1%;节肢动物门8种,占34.8%;软体动物门9种,占39.1%。尽管不同栖息环境中底栖动物的优势种有较大变化,但霍甫水丝蚓(Limnodrilus hoffmeisteri)、苏氏尾鳃蚓(Branchiura sowerbyi)和铜锈环棱螺(Bellamya aeruginosa)为整个巢湖流域优势物种。河流综合生物污染指数评价结果表明,巢湖流域水体均已受到不同程度的污染,南淝河的污染程度>白石山河>派河>巢湖湖体>柘皋河>杭埠河>裕溪河>丰乐河,这一结果与水质指标评价结果基本一致。  相似文献   

20.
Summary Spruce (Picea abies) damage in the Fichtelgebirge (FRG) occurs as needle bleaching and a depression of CO2 assimilation. Such injury may primarily result from the direct, above-ground effects of air pollution or indirect, below-ground changes in mineral uptake.Typically, the new flush of spruce needles is green and exhibits high photosynthetic capacity. Mies and Zöttl concluded that the older foliage is damaged when nutrients are withdrawn to supply the current year's needles. By removing the terminal buds of single branches in the spring, we produced an experimental set of the previous year's needles with greater mineral reserves than the control needles. During the course of the growing period, the performance of the experimental needles, which lacked competition from the new flush, was compared to that of the control needles of the same age-class on intact branches with the new flush.Throughout the experiment, chloroplast pigments of a healthy control tree were not affected by the elimination of the new flush. However, the chlorophyll and carotenoid content as well as the photosynthetic capacity of the previous year's needles on those branches of a heavily damaged tree where the new flush had been eliminated increased substantially. This increase was associated with an increase in minerals, which seemed to be deficient in the control needles with the new flush. Thus, in contrast to needles of the same age-class on intact branches with undisturbed new growth in the same atmospheric environment, the experimental needles escaped bleaching and a decrease in photosynthesis. It would seem that the bleaching and the loss in photosynthetic capacity typical of trees damaged by forest decline indirectly result from nutrient deficiencies through soil environment changes and/or root damage than directly from atmospheric pollutants.  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