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 500 毫秒
1.
在群落调查的基础上,分析了古田山自然保护区常绿阔叶林的群落类型和群落物种多样性特征.结果表明:古田山自然保护区常绿阔叶林主要有6种类型(群系),即甜槠林、栲树林、野含笑-钩栗林、青冈林、虎皮楠-甜槠林、乌冈栎-青冈林,并对各群落类型的结构和物种组成进行了描述.从各群落的外貌、结构和种类组成上看,均具有我国典型常绿阔叶林的基本特征.不同群落类型其物种多样性大小不同,栲树林和野含笑-钩栗林物种多样性较高,虎皮楠-甜槠林和乌冈栎-青冈林物种多样性较低.在群落垂直结构中,灌木层→乔木层→草本层物种多样性依次降低,乔木层与灌木层之间物种多样性差异不显著,草本层的物种丰富度、物种多样性指数均明显小于乔木层和灌木层.与邻近4个山地常绿阔叶林物种多样性相比较,古田山常绿阔叶林物种多样性比纬度位置高的黄山和大别山要大,但比纬度位置低的乌岩岭和缙云山小.  相似文献   

2.
大蒜培养细胞对水杨酸的应答比对温度和水分胁迫的应答更为强烈,其主要特征是抗氧化酶类超氧化物歧化酶的大量生成,同时还观察到水杨酸对冷胁迫或热休克介导的酶诱导作用的强化.上述结果暗示着自由基的生成是环境胁迫作用于植物细胞的机制之一,水杨酸诱导产生的抗氧化活性高于冷胁迫或热休克.这表明化学胁迫可能以一种与物理胁迫不同的方式诱导超氧化物歧化酶同工酶的生成  相似文献   

3.
农业增长对资源依赖的变化趋势以及农业发展与环境的互动关系日益引起学术界的关注.运用脱钩理论,以2000-2005和2005-2010年为时间尺度,以县域为空间尺度,探讨黄淮海平原农业碳排放与经济增长之间的脱钩关系,揭示两者脱钩发展的时间和空间演变趋势及转移特征,并尝试分析脱钩的内在机理.结果表明:(1)脱钩类型的数量结构和空间格局均发生明显变化,黄淮海平原农业正处于由资源依赖向技术依赖的过渡时期.2000-2005年农业碳排放与经济增长以强复钩和扩张性复钩为主,脱钩空间格局较为分散;2005-2010年以强脱钩和弱脱钩为主,脱钩区域呈现空间集聚态势;若考虑因技术进步带来的碳排放系数变化因素,脱钩趋势将会更加明显.造成这种空间格局的原因主要是经济增长与环境的关系较为复杂,经济发展、技术进步和制度创新等因素通过互动机制共同作用于农业生产经营主体.(2)脱钩类型的转换呈跳跃性,转换方式以强复钩、扩张性复钩转换为强脱钩、弱脱钩为主,且脱钩状态不稳定,持续脱钩难度较大.脱钩状况受到经济效应、技术效应和政策效应等因素的共同作用,3者作用的两面性是持续脱钩难的重要原因.  相似文献   

4.
构建山东省循环经济建设的生态效率评价指标体系,对山东省的生态效率进行测度,并探讨经济发展与环境压力的脱钩/复钩关系.结果表明,2000-2010年,山东省GDP呈快速增长趋势,年均增长率达13.08%,各自然输入要素中用水总量、SO2和COD排放量呈下降趋势.各类自然输入要素的生态效率总体呈逐步提高趋势,其中COD排放、SO2排放和用水总量的生态效率年均增长率分别达18.59%、14.85%和14.13%,这3个指标处于强脱钩状态,其他指标均处于弱脱钩状态.总体而言,经济增长与环境保护的矛盾有所缓解,但能源的大量投入导致碳排放压力仍较大.  相似文献   

5.
孙立广  邢光熹 《环境化学》1996,15(3):254-259
高硫燃料煤烟气中的CO2是大气CO2的一个重要来源。烟气中的SO2是导致南方酸雨的主要原因^「1,2」,酸雨增强了地表水地下水对石灰岩的溶蚀,间接地释放出CO2,研究表明,:S,C在自然界面上循环,可通过酸雨作用于碳酸盐岩石来,我国南方高硫燃料煤所形成的酸雨对石灰岩地区每年将间接释放出(6.48-6.73)×10^10molCO2,从全球范围来看,受酸雨影响的石灰岩溶蚀量是温室气体CO2的一个不容  相似文献   

6.
生物修复技术研究进展   总被引:46,自引:2,他引:46  
生物修复在治理受有毒有害有机物污染的环境的作用日益突出,因而生物修复的研究愈加受到重视。文中对生物修复的发展情况进行了综述,涉及生物通气法、生物注射法、污染地下水及其上部污染土壤的生物修复系统、地耕处理、植物生物修复、堆肥法、生物反应器和厌氧处理等方面.同时就遗传工程微生物系统等方面研究对发展生物修复技术的意义作了展望.  相似文献   

7.
从40条随机引物筛选出6条,对暴露于蒽醌(0.0195mol/L)和十二烷基苯磺酸钠(100mg/L)海水溶液的鲈鱼基因组DNA进行RAPD扩增反应,检测DNA受损情况.实验结果显示,在蒽醌暴露实验中,引物OPA-03检测到鲈鱼在污染7d时的血液和肝脏DNA受到损伤,扩增结果缺失片段大小约为0.9kb特征带.在十二烷基苯磺酸钠污染实验中,不论是作用于鲈鱼个体,还是直接污染其DNA,用所筛选出的6条引物扩增结果未发现对基因组DNA造成损伤,图3表1参22  相似文献   

8.
重视生态策略在建筑设计中的运用   总被引:1,自引:0,他引:1  
周玉梅  修长春 《生态环境》2004,13(3):449-451
建筑既作用于生态环境,也作用于人类,它始终持续地影响着周围的环境和使用者的生活,特别是对于我国高速发展的城市来说,其影响更是巨大。生态建筑将成为21世纪建筑设计的主流。建筑与可持续发展的三个重要方面(环境保护、经济发展和社会进步)密切相关,生态建筑应是可持续发展的一个组成部分。文章针对我国生态环境与建筑设计中存在的主要问题,提出在建筑设计中要注重生态策略的运用,推动生态建筑设计要依靠全社会生态意识的提高,增强人与自然环境的沟通,完善生态建筑设计的法律规范。  相似文献   

9.
表面活性剂对采油区土壤装填土柱中PAHs迁移渗透的影响   总被引:4,自引:0,他引:4  
以阴离子表面活性剂十二烷基苯磺酸钠(LAS)对采油区土壤(MGP)中PAHs的淋洗效果进行研究.结果表明,5CMC(临界胶束浓度)LAS促进了土柱中PAHs的迁移渗透,土柱中PAHs的淋溶率较低,而且仅土柱上层5cm的土样中PAHs发生了较为明显的淋溶.与Br^-离子穿透曲线相比,土柱中PAHs的淋溶均有滞后现象,而且随着环数的增加,PAHs的淋溶滞后现象愈加明显.PAHs的迁移渗滤性与其辛醇/水分配系数之间具有显著负相关性,说明随着辛醇/水分配系数的增加,PAHs的淋溶率逐渐降低.  相似文献   

10.
部分氮杂环类化合物的遗传毒性及其QSAR研究   总被引:1,自引:0,他引:1  
朱春媚  沈其龙 《环境化学》1997,16(2):142-145
本文利用蚕豆细胞微核试验评价了10种氮杂环类化合物的遗传毒性,一化合物的最低未占据轨道能Elumo、分子的量负的原子净电荷q建立了较好的相关方程:MN=-2.96(1.14)+4.93(0.48)Elumo+13.68(2.72)q^-R^2=0.94 SE=0.71 F=53.92 P〈0.0005推测此类化合物的至于致毒机制可能是它们作为电荷给予体和氢键予体作用于生物受体而引起的突变。  相似文献   

11.
利用新复合引发体系合成P(DMDAAC-AM)共聚物   总被引:1,自引:0,他引:1  
采用新的复合引发体系及助剂,在水溶液中合成了分子量较高而且速溶的P(DMDAAC-AM)共聚物.着重研究各种引发剂和助剂的浓度、引发及烘干温度、反应时间等因素对聚合反应的影响,得出最佳合成工艺及配方.利用IR、透射电镜和扫描电镜对产品进行分析.  相似文献   

12.
新型甲醛捕获剂的合成及其捕获性能研究   总被引:1,自引:0,他引:1  
游离甲醛是室内空气中最主要的污染物之一,对人体造成的危害越来越受到关注.因此,研制新型甲醛捕获剂及其捕获性能具有重要的实际意义.采用亲水性单体丙烯酰胺和亲油性单体苯乙烯为反应物,以氧化还原引发剂,经霍夫曼降解反应合成了含氨基的两亲性共聚物.通过单因素实验考察了不同原料比、引发剂剂量时所合成的产物对人造板游离甲醛捕获率的影响,然后根据单因素实验的结果设计正交试验以优化合成条件.结果表明:苯乙烯单体和丙烯酰胺单体的摩尔比为1:3,引发剂与单体摩尔比为9%,丙烯酰胺单体和NaClO的摩尔比为1:1.2时产品捕获率最好,可达60.40%.实验合成的两亲性共聚物在常温下不挥发,相对稳定而且捕获效果较好,是一种理想的新型甲醛捕获剂.  相似文献   

13.
The ecotoxicities of three organic compounds containing spacer groups, an intermediate organotin premonomer, four organotin monomers, their homopolymers and six copolymers of tributylin α‐chloroacrylate (TCA) are reported against two microorganisms viz., Pseudomonas aeruginosa and Sarcina lutea and a larval species Anemia salina (Nauplii II). The organic compounds containing spacer group were less toxic whereas the monomers were found to be highly toxic. The homopolymers were found to be more toxic than that of tributyltin acrylate (TBTAA), tributyltin methacrylate (TBTMA) and tributyltin α‐Chloroacrylate (TCA). The toxicity of TCA copolymers increased with the increase in tributyltin (TBT) content in the polymer. From this study it was not possible to establish any relationship between the chemical nature of the comonomer with its toxicity.  相似文献   

14.
2007年2月在攀枝花市不同功能区采集了大气PM10样品42个和污染源样品32个,采用超声抽提GC/MS方法测定分析了16种多环芳烃(PAHs)的含量。结果显示攀枝花市PM10颗粒相PAHs单体浓度范围为0.34~416.45ng/m3,总量浓度范围为24.56~2569.66ng/m3;攀枝花市5个采样点中河门口片区PM10多环芳烃单体浓度范围为5.64~416.45ng/m3,污染最严重。源样品测定结果分别为扬尘78.74ug/g,煤烟尘6.12ug/g,钢铁工业尘30.54ug/g,焦化尘3187.42ug/g。应用比值法和化学质量平衡(CMB)模型对污染源进行识别,燃煤和炼焦是攀枝花市PAHs的主要来源,对攀枝花市大气可吸入颗粒物中多环芳烃污染的分担率分别为55.8%、19.9%。  相似文献   

15.
The release of pollutants from sewage sludge in the treatment process is a worldwide tricky problem in the field of sludge treatment. In this paper, the release and reaction between monomers of polycyclic aromatic hydrocarbons (PAHs) in the sewage sludge incineration treatment were studied based on simulated experiments. The result indicates that the transformation may occurre between monomers of PAHs during their release in the treatment. Over 90% of total PAHs in sewage sludge are released at the the temperature of 300°C–750°C. The possible transformation of Naphthalene to indeno(1, 2, 3-cd)pyrene was related to the temperature of the treatment system. Here, we showed that the output rate of transformation reactions for indeno(1, 2, 3-cd)pyrene is 94% at 300°C. These findings, by identifying corresponding treatment conditions as well as techniques, can help to understand the reactions and control real outputs of PAHs in the treatment process.  相似文献   

16.
Irwin RE  Adler LS 《Ecology》2008,89(8):2207-2217
Pollen movement within and among plants affects inbreeding, plant fitness, and the spatial scale of genetic differentiation. Although a number of studies have assessed how plant and floral traits influence pollen movement via changes in pollinator behavior, few have explored how nectar chemical composition affects pollen transfer. As many as 55% of plants produce secondary compounds in their nectar, which is surprising given that nectar is typically thought to attract pollinators. We tested the hypothesis that nectar with secondary compounds may benefit plants by encouraging pollinators to leave plants after visiting only a few flowers, thus reducing self-pollen transfer. We used Gelsemium sempervirens, a plant whose nectar contains the alkaloid gelsemine, which has been shown to be a deterrent to foraging bee pollinators. We found that high nectar alkaloids reduced the total and proportion of self-pollen received by one-half and one-third, respectively. However, nectar alkaloids did not affect female reproduction when we removed the potential for self-pollination (by emasculating all flowers on plants). We then tested the assumption that self-pollen in combination with outcrossed pollen depresses seed set. We found that plants were weakly self-compatible, but self-pollen with outcrossed pollen did not reduce seed set relative to solely outcrossed flowers. Finally, an exponential model of pollen carryover suggests that high nectar alkaloids could benefit plants via increased pollen export (an estimate of male function), but only when pollinators were efficient and abundant and plants had large floral displays. Results suggest that high nectar alkaloids may benefit plants via increased pollen export under a restricted set of ecological conditions, but in general, the costs of high nectar alkaloids in reducing pollination balanced or outweighed the benefits of reducing self-pollen transfer for estimates of female and male reproduction.  相似文献   

17.
以珠江河口水生食物链较顶端的鱼类和虾类作为研究对象,利用气相色谱(GC-ECD)法检测分析了有机氯农药滴滴涕(DDTs)和六六六(HCHs)及其单体在这些水生动物体内的残留水平和特征,以期为珠江流域水生生物生态风险评价提供基础资料和科学依据。结果显示,鱼类肌肉中的DDTs含量(以湿质量计)范围为未检出(nd)~42.73μg.kg-1(平均值为7.61μg.kg-1),在虾类肌肉中的含量范围为nd~9.51μg.kg-1(平均值为1.97μg.kg-1);鱼类肌肉中的HCHs含量范围为nd~1.71μg.kg-1(平均值为0.62μg.kg-1),在虾类肌肉中的含量范围为nd~0.86μg.kg-1(平均值为0.56μg.kg-1)。鱼类肌肉中DDTs和HCHs的残留均值高于虾类,而鱼类和虾类体内DDTs的残留量均高于HCHs的残留量。HCHs、DDTs的单体分别以γ-HCH、p,p'-DDT的含量最高,而且近期都有新的污染源输入。所采集的水产品中DDTs、HCHs残留量尚低于我国的无公害水产品质量安全标准要求(GB18406.4),亦低于日本、欧盟等发达国家和地区相关的最大残留限量,因此,DDTs、HCHs通过膳食的暴露暂时不会对该地区的人体健康产生危害。  相似文献   

18.
一种嗜热细菌来源角质酶的分离纯化及酶学性质   总被引:1,自引:0,他引:1  
通过跟踪发酵液中pNPB水解酶活性,对角质诱导的Thermobifida fusca 口发酵液进行分离纯化.采用活性炭脱色、硫铵沉淀、Phenyl HP疏水色谱、DEAE sephamse阴离子交换色谱等方法,分离纯化得到电泳纯PNPB水解酶.该酶水解角质可得到角质单体,是一种角质酶.SDS-PAGE电泳结果显示,角质酶表观分子量约为29×10~3.该酶的最适温度为60℃.在40℃和60℃下均具有良好的热稳定性.最适pH为8.0,pH稳定范围为6.0~9.0.该角质酶的生化性质适合在纺织工业中应用.图8表2参17  相似文献   

19.
Quantitative analysis of cadmium in environmental samples was achieved with a polymeric sorbent synthesized by copolymerization of N,N-dimethylacrylamide and allyl glycidyl ether/iminodiacetic acid as chelating monomers with N,N′-methylenebisacrylamide as cross-linker. The polymer was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, elemental analysis, and scanning electron microscopy. The sorption capacity of the functionalized sorbent was 70 mg g?1. The equilibrium sorption data of Cd(II) on polymeric sorbent were analyzed using Langmuir, Freundlich, Temkin, and Redlich–Peterson models. Based on equilibrium adsorption data, the constants at pH 4.2 and 20 °C were determined for the first three as 0.33 (L mg?1), 17.5 (mg g?1) (L mg?1)1/n, and 12.9 (J mol?1). Recovery of 94% of the metal ion was obtained with 0.5 mol L?1 nitric acid as an eluting agent.  相似文献   

20.
The alkali-soluble polysaccharides of the cell wall from 7 different marine diatoms were shown to contain the monosaccharides rhamnose, fucose, galactose, mannose and xylose. The relative amounts of rhamnose and fucose varied widely from one species to another, from the very rhamnose-rich Chaetoceros affinis to Thalassiosira gravida, where no rhamnose was found. All Chaetoceros species were found to have a high content of rhamnose. Also the proportion of mannose to galactose varied widely from species to species. The observed change in monomer composition from the logarithmic to the stationary growth phase is explained by assuming the alkali-soluble fraction to be a mixture of polysaccharides. The soluble, extracellular polysaccharides from 4 of the diatoms were also investigated. The products from C. affinis and C. curvisetus were homogeneous and composed of only 3 monomers: rhamnose, fucose and galactose. The extracellular polysaccharide composition in all species investigated was quite different from the composition of the cellular alkali-soluble fraction. The ecological aspects of these soluble polysaccharides may prove of considerable interest.  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