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1.
共存离子对硫酸盐还原菌(SRB)处理含铬废水的影响研究   总被引:9,自引:0,他引:9  
报道了用硫酸盐还原菌(SRB)处理含铬(VI)废水时,共存离子Sr^2+,Cd^2+,Zn^2+,UO^2+2,Ag^+和Cl^-,SO2-4,CO^2-3,SiF^2-6,EDTA柠檬酸根等存在的时的影响,在铬(VI)为50μg/mL,菌量一定的条件下,铬的去除率可达85%以上,共存离子与铬(VI)的摩尔比为4时影响较为显著,Cd^2+和Ag^+使铬的去除量降低,UO^2+2,Sr^2+,Zn^  相似文献   

2.
荧光光纤传感器测定废水中邻硝基苯酚   总被引:1,自引:0,他引:1  
将2-(4-二苯基)-6-苯基苯并恶唑包埋在增塑的PVC膜中,基于邻硝基苯酚对PBBO荧光的猝灭,研制了一种邻硝基苯酚荧光光纤传感器。该传感器对邻硝基苯酚的响应具有良好的可逆性和重现性,响应时间小于50s,在1.2*10^-4-2.0*10-6mol/L邻硝基苯酚浓度范围内具有好的线性关系。环境水中可能存在的常见阳离子、阴离子、酚、硝基化合物对邻硝基苯酚的测定不产生干扰,将传感器用于废水中的邻硝基  相似文献   

3.
本文根据辐射传热和对流传热理论,利用Matlab 程序结合太阳能热水器本身的尺寸以及与其有关的水和空气的物理弹性详细分析了影响平板式太阳能热水器热效率的因素包括太阳能热水器表面的太阳光辐射的吸收率αs 和辐射系数ε,太阳能热水器的水进口温度Tc,in和流量mc 太阳辐射能力Gs,,环境大气温度Te,大气辐射系数εsky 以及太阳能热水器内部的总传热系数U。分析结果表明较高的太阳照射能力、环境温度和总传热系数有利于提高集热效率,而增加水量和水进口温度、热水器辐射系数和大气辐射系数则有相反的效果。  相似文献   

4.
重金属污染与指示植物   总被引:1,自引:0,他引:1  
一、植物与化学元素重金属污染物在环境中不能被生物降解,只能在价态和形态上发生转化,并且可以在生物体内富集积累。因此,对人类的健康与生存带来潜在性的威胁。现在世界上对重金属污染问题十分重视。研究重金属对生态系统的影响是环境科学的重要课题。在自然环境中,植物的发育、生长和繁殖需要一定的营养。而各种植物所需要的营  相似文献   

5.
研究了好氧,缺氧,厌氧三种状态下土壤含水层处理工艺对北京高碑店污水处理厂二级出水中有机物的去除效果,BOD5去除率大于905,COD,DOC,UV-254去除率12%-25%之间,厌氧状态下,通过共代谢作用,可去除约55%的AOX;好氧状态下,出水NH3-N浓度低于0.5display status  相似文献   

6.
土壤和植物中镉的污染及防治   总被引:11,自引:0,他引:11  
阐述了镉在土壤中的含量与形态,镉对植物的毒害效应,各种植物对镉富集能力,以及植物对镉的吸收和在不同器官的积累差异,还综述了镉对植物叶细胞超微结构的影响,提出了防治农业生态系统中镉污染的方法。  相似文献   

7.
辐射环境是生态环境的重要组成部分,核与辐射环境安全是国家环境安全的重要内容.详述了目前浙江省辐射环境监测网络的建设情况,以及对核设施、铀矿及伴生矿放射性污染源、核技术运用、电磁辐射环境、辐射应急等进行辐射环境监测的情况,分析了存在的主要问题,并提出了相应的对策,为浙江省辐射环境监管提供技术支撑和科学依据,同时也对全国辐射环境监测和管理具有积极的指导意义.  相似文献   

8.
研究水体DO及其分布情况对水质保护与富营养化治理意义重大。基于近自然湿地植物和明水区域的定期野外调查,分析明水与植物区域内DO含量时空分布特征及不同区域DO含量与水温、pH和叶绿素a含量的响应关系,探讨湿地挺水植物对DO含量的影响及其影响因素。结果表明:研究区域DO月平均质量浓度为6.43~13.76mg/L,植物区域DO含量总体低于明水区域;湿地挺水植物群落通过区域水温、pH和叶绿素a含量的综合调节作用影响区域耗氧和复氧过程,对DO分布特征有一定的调节作用。  相似文献   

9.
植物细胞色素P450酶系的研究进展及其与外来物质的关系   总被引:13,自引:1,他引:12  
植物细胞色素P450是分子量为40-60KD、结构类似的一类血红素-硫铁蛋白。它以可溶性和膜结合两种形态存在于植物细胞内,可催化多种化学反应,在防御植物免受有害物质侵害方面具有重要作用。目前已克隆90多个植物细胞色素P450基因。本文概述了植物P450基因表达调控与环境、发育、组织特异性关系的研究进展。认为植物P450同工酶在环境毒物生物修复和在抗外源毒素的转基因植物方面具有很高的应用前景。  相似文献   

10.
微波辐射加热合成蒽醌的清洁生产正交实验研究   总被引:1,自引:0,他引:1  
微波辐射加热合成蒽醌反应,速度快、产率高、无污染,是一种很有应用价值的清洁生产方法。观测了微波辐照条件下蒽醌产率的变化情况及影响因素,着重研究了邻苯甲酰苯甲酸环化脱水缩合生成蒽醌的最佳反应条件及蒽醌产率与影响因素间的关系。  相似文献   

11.
The term 'global climate change' encompasses many physical and chemical changes in the atmosphere that have been induced by anthropogenic pollutants. Increases in concentrations of CO2 and CH4 enhance the 'greenhouse effect' of the atmosphere and may contribute to changes in temperature and precipitation patterns at the earth's surface. Nitrogen oxides and SO2 are phytotoxic and also react with other pollutants to produce other phytotoxins in the troposphere such as O3 and acidic substances. However, release of chlorofluorocarbons into the atmosphere may cause depletion of stratospheric O3, increasing the transmittance of ultraviolet-B (UV-B) radiation to the earth's surface. Increased intensities of UV-B could affect plants and enhance photochemical reactions that generate some phytotoxic pollutants. The role of mycorrhizae in plant responses to such stresses has received little attention. Although plans for several research programs have acknowledged the importance of drought tolerance and soil fertility in plant responses to atmospheric stresses, mycorrhizae are rarely targeted to receive specific investigation. Most vascular land plants form mycorrhizae, so the role of mycorrhizae in mediating plant responses to atmospheric change may be an important consideration in predicting effects of atmospheric changes on plants in managed and natural ecosystems.  相似文献   

12.
Experimental results from plants receiving elevated doses of UV-B radiation generally show that Mediterranean forest species are well protected against increases in UV-B radiation. Natural adaptations to water stress and excess light (elevated concentrations of UV-B screening compounds, leaf hairs, thick cuticle and epidermis), and UV-B responses (thickening of the cuticle, increase in carotenoids) may avoid or counter-balance UV-B radiation damage. This response confirms that Mediterranean forest vegetation is adapted to face oxidative stress factors, such as elevated tropospheric ozone concentrations, drought and high radiation, including UV-B. Nevertheless, in the long term, species-specific and season-specific differential responses in growth, physiology, phenology and reproductive behaviour may alter the interactions between species and lead to slow but important changes in ecosystem structure and function.  相似文献   

13.
The projected doubling of current levels of atmospheric carbon dioxide concentration ([CO(2)]) during the next century along with increases in other radiatively active gases have led to predictions of increases in global air temperature and shifts in precipitation patterns. Additionally, stratospheric ozone depletion may result in increased ultraviolet-B (UV-B) radiation incident at the Earth's surface in some areas. Since these changes in the Earth's atmosphere may have profound effects on vegetation, the objectives of this paper are to summarize some of the recent research on plant responses to [CO(2)], temperature and UV-B radiation. Elevated [CO(2)] increases photosynthesis and usually results in increased biomass, and seed yield. The magnitude of these increases and the specific photosynthetic response depends on the plant species, and are strongly influenced by other environmental factors including temperature, light level, and the availability of water and nutrients. While elevated [CO(2)] reduces transpiration and increases photosynthetic water-use efficiency, increasing air temperature can result in greater water use, accelerated plant developmental rate, and shortened growth duration. Experiments on UV-B radiation exposure have demonstrated a wide range of photobiological responses among plants with decreases in photosynthesis and plant growth among more sensitive species. Although a few studies have addressed the interactive effects of [CO(2)] and temperature on plants, information on the effects of UV-B radiation at elevated [CO(2)] is scarce. Since [CO(2)], temperature and UV-B radiation may increase concurrently, more research is needed to determine plant responses to the interactive effects of these environmental variables.  相似文献   

14.
Research has shown that some plants respond to enhanced UV-B radiation by producing smaller and thicker leaves, by increasing the thickness of epidermis and concentration of UV-B absorbing compounds of their surface layers and activation of the antioxidant defence system. The response of high-altitude plants to UV-B radiation in controlled conditions is often less pronounced compared to low-altitude plants, which shows that the alpine timberline plants are adapted to UV-B. These plants may have a simultaneous co-tolerance for several stress factors: acclimation or adaptation to the harsh climate can also increase tolerance to UV-B radiation, and vice versa. On the other hand, alpine timberline plants of northern latitudes may be less protected against increasing UV-B radiation than plants from more southern latitudes and higher elevations due to harsh conditions and weaker preadaptation resulting from lower UV-B radiation exposure. It is evident that more long-term experimental field research is needed in order to study the interaction of climate, soil and UV-B irradiance on the timberline plants.  相似文献   

15.
Although terrestrial vegetation has been exposed to UV-B radiation and ozone over the course of evolutionary history, it is essential to view the effects on vegetation of changing levels of these factors in the context of other features of climate change, such as increasing CO(2) levels and changes in temperature and precipitation patterns. Much of our understanding of the impacts of increased UV-B and ozone levels has come from studies of the effects of each individual factor. While such information may be relevant to a wider understanding of the roles that these factors may play in climate change, experience has shown that the interactions of environmental stresses on vegetation are rarely predictable. A further limitation on the applicability of such information results from the methodologies used for exposing plants to either factor. Much of our information comes from growth chamber, greenhouse or field studies using experimental protocols that made little or no provision for the stochastic nature of the changes in UV-B and ozone levels at the earth's surface, and hence excluded the roles of repair mechanisms. As a result, our knowledge of dose-response relationships under true field conditions is both limited and fragmentary, given the wide range of sensitivities among species and cultivars. Adverse effects of increased levels of either factor on vegetation are qualitatively well established, but the quantitative relationships are far from clear. In both cases, sensitivity varies with stage of plant development. At the population and community levels, differential responses of species to either factor has been shown to result in changes in competitiveness and community structure. At the mechanistic level, ozone generally inhibits photosynthetic gas exchange under both controlled and field conditions, and although UV-B is also inhibitory in some species under controlled conditions, others appear to be indifferent, particularly in the field. Both factors affect metabolism; a common response is increased secondary metabolism leading to the accumulation of phenolic compounds that, in the case of UV-B, offer the leaf cell some protection from radiation. Virtually no information is available about the effects of simultaneous or sequential exposures. Since both increased surface UV-B and ozone exposures have spatial and temporal components, it is important to evaluate the different scenarios that may occur, bearing in mind that elevated daytime ozone levels will attenuate the UV-B reaching the surface to some extent. The experimentation needed to acquire unequivocal effects data that are relevant to field situations must therefore be carried out using technologies and protocols that focus on quantification of the interactions of UV-B and ozone themselves and their interactions with other environmental factors.  相似文献   

16.
Depletion of stratospheric ozone over the Antarctic has been re-occurring yearly since 1974, leading to enhanced UV-B radiation. Arctic ozone depletion has been observed since 1990. Ozone recovery has been predicted by 2050, but no signs of recovery occur. Here we review responses of polar plants to experimentally varied UV-B through supplementation or exclusion. In supplementation studies comparing ambient and above ambient UV-B, no effect on growth occurred. UV-B-induced DNA damage, as measured in polar bryophytes, is repaired overnight by photoreactivation. With UV exclusion, growth at near ambient may be less than at below ambient UV-B levels, which relates to the UV response curve of polar plants. UV-B screening foils also alter PAR, humidity, and temperature and interactions of UV with environmental factors may occur. Plant phenolics induced by solar UV-B, as in pollen, spores and lignin, may serve as a climate proxy for past UV. Since the Antarctic and Arctic terrestrial ecosystems differ essentially, (e.g. higher species diversity and more trophic interactions in the Arctic), generalization of polar plant responses to UV-B needs caution.  相似文献   

17.
Species individualistic responses to warming and increased UV-B radiation are moderated by the responses of neighbors within communities, and trophic interactions within ecosystems. All of these responses lead to changes in ecosystem structure. Experimental manipulation of environmental factors expected to change at high latitudes showed that summer warming of tundra vegetation has generally led to smaller changes than fertilizer addition. Some of the factors manipulated have strong effects on the structure of Arctic ecosystems but the effects vary regionally, with the greatest response of plant and invertebrate communities being observed at the coldest locations. Arctic invertebrate communities are very likely to respond rapidly to warming whereas microbial biomass and nutrient stocks are more stable. Experimentally enhanced UV-B radiation altered the community composition of gram-negative bacteria and fungi, but not that of plants. Increased plant productivity due to warmer summers may dominate food-web dynamics. Trophic interactions of tundra and sub-Arctic forest plant-based food webs are centered on a few dominant animal species which often have cyclic population fluctuations that lead to extremely high peak abundances in some years. Population cycles of small rodents and insect defoliators such as the autumn moth affect the structure and diversity of tundra and forest-tundra vegetation and the viability of a number of specialist predators and parasites. Ice crusting in warmer winters is likely to reduce the accessibility of plant food to lemmings, while deep snow may protect them from snow-surface predators. In Fennoscandia, there is evidence already for a pronounced shift in small rodent community structure and dynamics that have resulted in a decline of predators that specialize in feeding on small rodents. Climate is also likely to alter the role of insect pests in the birch forest system: warmer winters may increase survival of eggs and expand the range of the insects. Insects that harass reindeer in the summer are also likely to become more widespread, abundant and active during warmer summers while refuges for reindeer/caribou on glaciers and late snow patches will probably disappear.  相似文献   

18.
Approximately 35 species representing 14 tree genera have been evaluated for responses to UV-B radiation in North America. The best representation has been in the conifers where some 20 species representing three genera have been studied. Overall, about 1/3 of these have demonstrated some deleterious response to UV-B. However, most negative impacts have been observed under controlled environment conditions where sensitivity may be enhanced. Therefore, it seems unlikely that expected levels of ozone depletion will result in direct losses in productivity. However, the role that ambient or enhanced levels of UV-B may play in forest ecosystem processes is more difficult to access. One possible indirect response of forests to changes in UV-B radiation levels could be via alterations in plant secondary metabolites. Increases in phenolics and flavonoids that enhance epidermal UV-screening effectiveness may also influence leaf development, water relations or ecosystem processes such as plant-herbivore interactions or decomposition.  相似文献   

19.
Continued world population growth results in increased emission of gases from agriculture, combustion of fossil fuels, and industrial processes. This causes changes in the chemical composition of the atmosphere. Evidence is emerging that increased solar ultraviolet-B (UV-B) radiation is reaching the earth's atmosphere, due to stratospheric ozone depletion. Carbon dioxide (CO(2)), ozone (O(3)) and UV-B are individual climate change factors that have direct biological effects on plants. Such effects may directly or indirectly affect the incidence and severity of plant diseases, caused by biotic agents. Carbon dioxide may increase plant canopy size and density, resulting in a greater biomass of high nutritional quality, combined with a much higher microclimate relative humidity. This would be likely to promote plant diseases such as rusts, powdery mildews, leaf spots and blights. Inoculum potential from greater overwintering crop debris would also be increased. Ozone is likely to have adverse effects on plant growth. Necrotrophic pathogens may colonize plants weakened by O(3) at an accelerated rate, while obligate biotroph infections may be lessened. Ozone is unlikely to have direct adverse effects on fungal pathogens. Ozone effects on plant diseases are host plant mediated. The principal effects of increased UV-B on plant diseases would be via alterations in host plants. Increased flavonoids could lead to increased diseased resistance. Reduced net photosynthesis and premature ripening and senescence could result in a decrease in diseases caused by biotrophs and an increase in those caused by necrotrophs. Microbial plant pathogens are less likely to be adversely affected by CO(2), O(3) and UV-B than are their corresponding host plants. Changes in host plants may result in expectable alterations of disease incidence, depending on host plant growth stages and type of pathogen. Given the importance of plant diseases in world food and fiber production, it is essential to begin studying the effects of increased CO(2), O(3) and UV-B (and other climate change factors) on plant diseases. We know very little about the actual impacts of climate change factors on disease epidemiology. Epidemiologists should be encouraged to consider CO(2), O(3) and UV-B as factors in their field studies.  相似文献   

20.
Seedlings of Calamagrostis epigeios were exposed to four levels of UV-B radiation (280-320 nm), simulating up to 44% reduction of stratospheric ozone concentration during summertime in The Netherlands, to determine the response of this plant species to UV-B irradiation. After six weeks of UV-B treatment, total biomass of all UV-B treated plants was higher, compared to plants that had received no UV-B radiation. The increase of biomass did not appear to be the result of a stimulation of net photosynthesis. Also, transpiration rate and water use efficiency were not altered by UV-B at any exposure level. Pigment analysis of leaf extracts showed no effect of enhanced UV-B radiation on chlorophyll content and accumulation of UV absorbing pigments. UV-B irradiance, however, did reduce the transmittance of visible light (400-700 nm) of intact attached leaves, suggesting a change in anatomical characteristics of the leaves. Additionally, the importance of including an ambient UV-B treatment in indoor experiments is discussed.  相似文献   

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