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1.
The characteristics of the contents of 20 elements (Al, Fe, Mn, Ca, Mg, K, S, Si, P, Cd, Cu, Zn, Ti, Ni, Sr, Mo, Na, B, Cr, V) in 16 plant species collected from the Three Gorges Region in China were investigated. The average contents of Ca, K and Mg were higher than 1 000 μg·g-1, that of Al, P, Si, Fe, S and Mn ranged between 100—1 000 μg·g-1 and Ti, Cu, Ni, Cr, Mo, Cd and V were less than 10 μg·g- 1. The level of Na content was less than that of the reported. The main character of the element contents was of the Ca> K type. The contents of P, S, Ca and K in different plant samples showed a normal distribution pattern, while Al and Mn showed a elements lognormal distribution pattern. Plant species differed greatly in the element contents. On analyzing the coefficient of variation (C. V., % ), Al, Mn, Mg, Ni, Sr and Fe had higher C.V., while the C.V. of K, S, P, Cr, Cd and Cu was less than 60%, and Cu had the lowest C.V. The correlations between Al and Fe, Al and Ti, Al and Cr, A1 and V, Cd and Sr, Cd and Mo, Fe and V, Zn and Cr, Ni and Sr, Mg and Ni, Mo and Sr, Ca and Sr, Cr and Mo, Na and Mg, Na and P, P and S were statistically significant in different plant species. The classification of the 16 plant species and 20 dements by two-way indicator species analysis (TWINSPAN) method may suggest the difference in dement contents of the different plant species.  相似文献   

2.
The effects of compatibility, that is combination of Prunus persica Batsch (L.) and Carthamus tinctorus (L.), and different acidity of digestive site on the species, lipopily and bioavailability of coordinated complex of iron, manganese, and zinc in medical decoction were studied. In view of octanol, a long-chain alkanol, resembled as the configuration of carbohydrate and adipose in human body, the octanol- and water-solubility were used to define the species of trace element in phytomedicine, to identify the lipopily and bioavailability of trace element, and octanol-water system was adopted to study the distribution of trace element in decoction of P. persica Batsch (L.) (A), C. tinctorus (L.) (B), and combination of medicine A and B (C) in stomach and intestine. The total concentration, water- and octanol-solubility concentration of iron, manganese, and zinc in medicinal material A, B and C or its decoction under gastric and intestinal acidity, were determined respectively by flame atomic absorption spectrometry, analyzed and compared. The compatibility of medicine A and B enhances the extract percent, octanol-solubility concentration, and stability of coordinated complex of iron, manganese, and zinc. Different acidity of digestive site and compatibility of medicines impact on the ligands of iron, manganese, and zinc, then greatly affect the species and its quantification, the lipopily and bioavailability of trace element. Such influence is quite different for different trace element. Such factors, especially the concentration of octanol-solubility trace element, could be the basis of the dosage to avoid trace element overload.  相似文献   

3.
Plasma levels of testosterone (T), 17-β-estradiol (E2), progesterone (P4), dehydroepiandrosterone (DHEA), corticosterone (B), thyroxine (T4) and triiodothyronine (T3) were monitored during postnuptial and the prenuptial molt in domestic goose (Anser anser domesticus) in both sexes. 1. At the beginning of postnuptial molt (when the old, worn dawny-, and cover feathers' loss starts) in ganders, the levels of T, E2, P4 decrease while DHEA and B significantly increase. The elevated levels of T4 and low T3 concentrations characteristic of the last phase of the reproduction, remain unchanged. In layers, similar changes were observed, however, B decreases. 2. In the early phase of outgrowth of wing and cover feathers, plasma levels of T, E2 and P4 are low. Elevated B, DHEA and T4 concentrations decrease in ganders, while in layers DHEA increases and B and T4 levels remain unchanged. T3 increases in both sexes. 3. The subsequent intensive outgrowth period of wing- and cover feathers both in ganders and in layers is characterized by very low levels of T, E2, DHEA and T4, but P4 increased, and T3 concentration remain high. 4. At the end of postnuptial molt - when the outgrowth of dawny, cover-, and wing feathers stops - very low T, E2, P4, DHEA and T4 levels and and high T3 plasma levels were found in both sexes. Fast increase of plasma B was detected in ganders, while in geese, B concentration remain high. 5. During prenuptial molting (outgrowth of contour and tail feathers) low E2, P4 and T4, increasing T and DHEA, but very high T3 and B plasma concentration were measured in ganders. In layers, very low T, E2, P4, DHEA and T4 levels, and very high B and T3 levels were found. 6. At the beginning of the fall-winter sexual repose (postmolting stage) T, E2, P4, DHEA and T4 levels increase, T3 and B declines in both sexes. 7. In the subsequent phase of fall-winter period (preparatory stage) there is a further increase in T, P4 and T4, a fast increase of B and a decrease of E2, DHEA and T3 in ganders. In layers, T, P4 and DHEA decrease, B increases and the T4 and T3 do not change. 8. At the beginning of reproduction high T level, unchanged DHEA, slightly declined P4, and decreased E2, T4, T3 and a strong decline of B concentrations occur in ganders. In layers, T is further increased, E2 and P4 shows high levels, and, at the same time DHEA and T3 remain unchanged, while B and T4 decrease.  相似文献   

4.
中国种子植物内生真菌资源及菌植协同进化   总被引:4,自引:0,他引:4  
综述了中国种子植物内生真菌资源研究概况,比较了裸子植物和被子植物内生真菌种类,它们都具有肉座菌目(Hypocreales),粪壳菌目(Sordariales),散囊菌目(Eurotiales),毛霉目(Mucorales)及不产孢类(Myceliasterilia)内生真菌。裸子植物内生真菌涉及52个属,既包括高等的子囊菌和担子菌,也包括低等的卵菌(Oomycetes)和接合菌(Zygomycetes)类。被子植物涉及60个属,主要为高等的子囊菌(Ascomycetes)和担子菌(Basidiomycetes),低等的卵菌和接合菌报道很少。双子叶植物涉及40个属,单子叶植物内生真菌涉及30个属,两类被子植物所报道的内生真菌只有11个属相同。裸子植物与双子叶植物内生真菌相似程度较高,都具有炭角菌目(Xylariales)、格孢腔菌目(Pleosporales)、柔膜菌目(Helotiales)和白粉菌目(Erysiphales),刺盘孢菌属(Colletotrichum)、拟茎点霉属(Phomopsis)、枝孢霉属(Cladosporium)、地霉属(Geotrichum)等内真菌,共20个属相同。各类种子植物具有自己独特的一些内生真菌。还对植物与其内生真菌的协同进化关系进行了分析。  相似文献   

5.
The Cuban species of Calisto are reviewed based on the morphology of adult and immature stages, as well as DNA sequences of six genes (COI, EF1α, wingless, GAPDH, RpS5, CAD). A new species, Calisto occultasp. n., is described from the northeastern Cuban mountains. Calisto smintheus Bates, 1935 and Calisto bruneri, Michener 1949 are revised and revalidated. A new status, the species level, is proposed for Calisto brochei, Torre 1973, Calisto muripetens, Bates 1939 and Calisto bradleyi, Munroe 1950. The immature stages of Calisto smintheus, Calisto brochei,and Calisto occulta are described for the first time, and those of Calisto herophile, Hübner 1823 are redescribed. Useful morphological characters for adults are the shape and conspicuousness of androconial patch, the number and relative size of white dots on underside of hindwing, the shape of aedeagus, the shape of digitiform projection of genitalia valve, the shape and relative size of tegumen and uncus, the relative size of female genitalia, the height of sterigmal ring dorsal crown of the latter, and the relative size of corpus bursae and ductus bursae. For the immature stages, the most important characters are the color pattern of head capsule, the number and width of longitudinal lines of body, in the larvae; and the color pattern and the absence or presence of dorsal ridges on the abdomen of pupae. The phylogenetic relationships between the Cuban Calisto species are quite robust and well-supported; however, conflict between mitochondrial and nuclear datasets was detected in Calisto brochei, Calisto muripetens and to a lesser degree in Calisto bradleyi.  相似文献   

6.
现阶段中国生态农业可持续发展面临的实践和理论问题探讨   总被引:21,自引:0,他引:21  
章家恩  骆世明 《生态学杂志》2005,24(11):1365-1370
随着全球经济一体化的发展以及中国实施可持续发展和全面建设小康社会的需要,中国生态农业面临着新的机遇和挑战。我国生态农业经过20多年的实践,现已取得了一定进展,并具备了一定的发展基础。目前,全国2000多个县、乡镇先后实施了生态农业建设。然而,当前我国生态农业可持续发展面临着一系列实践和理论问题。在实践方面,存在着思想认识、技术、资金、建设与管理等问题。在科学理论方面则需要解决如生态农业的基本内涵、分类、生态模式的内在过程与机理及其生态服务功能、模式的尺度转换以及生态农业模式变化规律、生态农业安全等问题。因此,加快开展全国生态农业建设规划,加大资金投入和政策扶持力度,加强农业基础设施和社会化服务体系建设,加快农业产业结构调整和优化升级,发展生态产业,全面推动生态农业的产业化、标准化、信息化和现代化发展。是当前生态农业建设面临的重要任务。  相似文献   

7.
高程  郭良栋 《生物多样性》2022,30(10):22429-23168
微生物主要包括细菌、真菌、古菌、病毒等类群, 是地球上出现时间最早、分布最广泛、个体数量最多, 以及物种和基因多样性十分丰富的生物类群。为了适应各种生境, 微生物衍生出腐生、寄生、共生等多样的生存策略, 在生物地球化学循环、生态系统演替与稳定性、环境修复以及人类健康等方面发挥着重要作用。传统的微生物监测方法限制了我们对微生物多样性的认知; 但是, 近年来高通量测序技术和生物信息学的发展极大推动了微生物多样性的研究进展。本文概述了近年来在微生物多样性分布格局与维持、群落构建以及功能属性多样性的最新进展; 总结分析了细菌、古菌、真菌的多样性纬度分布格局及其驱动因子, 选择、扩散、成种、漂变等过程对细菌、古菌、真菌的群落构建的贡献, 以及细菌和真菌的形态、生理生化、生长繁殖、扩散、基因组等功能性状的多样性; 提出了未来微生物多样性研究的重要领域: 环境宏真菌组研究, 微生物多样性与生态系统多功能性的关系研究, 以及微生物互作网络的生态功能研究。  相似文献   

8.
This paper aggregates and compares findings on 300 groups of women studied in different parts of the world. Variables considered are stature, sitting height, head width and length, face width and height, shoulder and hip widths, and limb girths. Most of the groups were measured between 1950 and 1965. Mean stature approximates 137 cm to 139 cm on Bambuti women of Africa, Asai women of New Guinea, and Sierra de Parija women of South America. Means are near 143 cm for Pahira and Telefolmin women; 148 cm for Bundi, Quechua, and Vietnamese women; 154 cm for Ethiopian and Japanese women; and 159 cm for Coniagui, Italian, Jamaica Negroid, Polish, and Russian women. Groups taller than 162 cm include Amerind women of the Blackfeet tribe; European women of German, Norwegian, Swedish, and Swiss descent; and United States women of northwest European ancestry. The body stem component of stature is relatively short in Australian aborigines and women of several Negroid and Amerind tribes; relatively long in Japanese and Quechua women; and intermediate in women of India, Taiwan aborigines, and United States Caucasoid women. In mean head width, Apache women exceed Pahira women by 2.4 cm, or 18%. In head length, Easter Island natives average 2.0 cm, or 12% longer than Paiwan women of Taiwan. Means for biiliocristal diameter are below or near 24 cm on Bujeba, Hutu, Quechua, Shirisna, Tutsi, and Yecuana women, and above 28 cm on Basque, French, Hungarian, Sicilian, and United States Caucasoid women. For biacromial diameter, means are near 30 cm on Sinhalese women, and near 36 cm on several groups of European women.  相似文献   

9.
新建果园几种作物间种模式生态系统结构及功能研究   总被引:3,自引:2,他引:1  
从荒坡地新建果园10多种农作物间种模式中筛选出5种优化模式,分析和评价了各种种植模式的生态系统的结构和功能.结果表明,随着重复种植的增加,5种间种模式土壤有机质年增加5%一20%,全氮年增加7%一40%,全磷年增加8%一70%,全钾年增加15%一80%;水土保持最好的是花生-秋大豆、春大豆-秋大豆,其次为西红柿-白菜、辣椒-西红柿和早稻-红萝卜,土壤平均侵蚀量和地表径流量与对照相比分别降低44.19%、38.24%、39.52%、37.56%、37.30%和22.40%、9.28%、24.11%、21.60%、15.93%;在5种模式中,生物量最高的是辣椒—西红柿,年均达到100276kg.hm^-2,其次是花生-秋大豆,年均达到77026kg.hm^-2;而生产力最高的是花生—秋大豆,达到15619kg.hm^-2,其次是西红柿—白菜,为15394kg.hm^-2;投能效率最高的是辣椒—西红柿,年均达到3.06,其次为西红柿—白菜、花生—秋大豆、春大豆—秋大豆、早稻-红萝卜,分别为2.16、2.15、2.06和0.71.同时,有机、无机能输入效应表明,以生物能为主源输入进行转化利用太阳光能和水土资源,维护了果园生态系统的能量盈余,生态效益较高.  相似文献   

10.
利用方差均值比和修正的Clark-Evans最近邻体两种分布格局判定方法,对湖北省五峰县后河国家自然保护区1hmz固定样地中DBH≥5cm、重要值>2.5的26个树种的种群结构和分布格局类型进行了研究.结果表明,26个种群中有金钱槭、天师栗、白辛树、珙桐、领春木、水青树、连香树7种珍稀濒危植物种群和尖连蕊茶、君迁子、建始槭、曼青冈、鸡爪槭、桃叶黄杨、鹅耳枥等19种非珍稀濒危植物种群,7种珍稀植物种群中,除了2种个体较少的种群之外,1个种群为衰老型,其余4个种群均为增长型;3个种群呈随机分布类型,其余4个种群呈聚集分布类型,19个非珍稀植物种群中,1个种群为衰老型,6个种群为稳定型,其余12个种群为增长型;2个种群为随机分布类型,其余的17个种群为聚集分布类型.可见在26个种群中,以增长型种群居多(占66.7%),稳定型种群次之(占25.0%),衰老型种群最少(占8.3%);两种分布格局判定方法所得的结果较为一致,表现为种群的分布格局类型以聚集分布居多(占80.77%),随机分布和均匀分布较少。  相似文献   

11.
植被志是基于植被(或植物群落)调查资料, 全面记叙植被的外貌、物种组成、结构和功能, 以及地理分布和生境条件等特征, 并对同类植被进行归纳和总结的志书。《中国植被志》是第一部对中国植被进行全面记述的志书, 预计完成约48卷110册。在借鉴《中国植被》(1980)(简称“80方案”)植被分类基本原则的基础上,《中国植被志》将对中国植被分类系统的高级分类单位(植被型组、植被型和植被亚型)进行归纳和总结, 对中级和低级分类单位(群系组、群系、亚群系, 群丛组、群丛)进行详细描述。植被高级分类单位的描述具有概括性质, 是在中国植被分类系统中级和低级分类单位描述的基础上, 对其在全球和中国境内的地理分布、自然环境、群落外貌、植被类型及多样性、优势种或共优势种、生物多样性保育价值以及资源现状等进行概述, 并对“80方案”相关内容进行修订和拓展, 将提供对中国植被基本特征客观、准确的记述。在植被中级和低级分类单位中, 群系组描述的内容包括地理分布、自然环境、群落外貌、植被类型以及价值与保育等内容; 群系描述的主要内容包括地理分布、自然环境、生态特征、物种组成、群落结构、群丛组和群丛的分类与描述、优势种的生物学特性、生物量与生产力、植被动态与演替以及价值与保育等方面。作为植被志研编的核心内容, 群丛组和群丛的分类与描述主要基于植被调查资料, 采用数量分类方法, 根据群落结构和物种组成的差异划分出不同的植被类型, 并对其基本特征进行定量描述和归纳。其中, 群落的层片结构、特定植被分类单元的特征种或特征种组的筛选与甄别是植被类型划分的关键环节; 而群落外貌, 群落结构, 物种组成, 各类物种的生长习性、生境的偏适性等是群丛组和群丛描述与归纳的重点内容。该文提出了中国植被中级和低级分类单位的命名方案, 其特点在于植被类型的科学名称中同时体现了植被分类单元特征种或优势种的名称及其所属的高级植被分类单位(植被型组或植被型)的名称, 兼顾了植被名称的规范性与实用性。《中国植被志》的研编工作由文献整编、群落调查、数据分析与整理、文本撰写等环节组成。该文对植被样方的调查与收集, 文献收集与整编, 气候、土壤、地形等相关数据的来源及其整理方法, 植被分类方法, 植被命名, 植被分类单元描述的内容, 植被志章节编写大纲、体裁及撰写等多个规范进行了详细的阐述或示例。  相似文献   

12.
(山弄)岗植物区系考察报告   总被引:4,自引:3,他引:1  
<正> 前言 一、鼻岗植物区系的组成 (一)科、属、种的统计 (二)10种以上的科的统计 (三)含10种以上的科在世界区系中的比重 (四)含10种以上的科在广西区系中的比重 (五)木本植物统计。 二、鼻岗植物区系的特点 (一)热带边缘性质 (二)特有性 (三)岩溶特性 三、鼻岗植物区系的地形分布特点及生态变化 (一)谷地、山坡、崖顶的分布概况 (二)水平分布的差异 (三)生态变化 四、鼻岗植物区系与邻近地区植物区系的关系 (一)与中印半岛的关系 (二)与海南岛的关系 (三)与广西阳朔的关系 (四)与花坪的关系 (五)与马来半岛岩溶植物区系的关系 (六)总的比校  相似文献   

13.
生态环境损害事件会破坏或者损害动植物生境与生态系统平衡,乃至对我国生态安全造成威胁。然而目前针对森林生态系统损害鉴定评估工作存在评估体系不完善、定量化评估方法不足、损害赔偿管理制度不健全等问题,且缺乏对人类活动与森林生态系统相互作用的整体受损情况进行剖析。基于此,综合考量人类活动与森林生态系统状况的受损范畴与界限,剔除其中交叉重复的内容,遵循科学性、系统性、可比性、可操作性等4项原则,构建了森林生态系统损害评估指标体系。该体系基于受损对象,涉及了人身安全损害、人类活动损害、森林生态系统功能损害和其他损害共计4项一级指标,包括身体损害、精神损害、经济林果品损失、林副产品损失、加工制造业损失、森林旅游损失、科研文史损失、土壤保持损失、水源涵养损失、防风固沙损失、固碳释氧损失、大气净化损失、应急处理费、调查评估费共14项二级指标,以及22项三级指标,并运用市场价值法、替代成本法、影子工程法、恢复成本法等方法明确了各项指标的价值量化方法。文章还从林业技术部门和司法行政部门两个方面,对森林生态系统损害管理制度进行了探讨。林业技术部门管理制度主要分为事前预防、事中响应和事后评估,包括安全规划、风险控制、损害溯源、应急救援措施、技术方案与修复标准制定等;司法行政部门管理制度主要分为监督管理、立法管理和社会机制,包括名册记录(编制)、违法违规追责、赔偿制度完善、森林损害基金和公众参与办法的建立等。旨在为森林生态系统损害评估技术的定量化、标准化,以及管理制度的健全化提供参考依据。  相似文献   

14.
Because of some catastrophic events which occurred in Mexico during the 1980 decade, the utilization of "tepescohuite" bark against skin wounds and burns was popularized. The media manipulated the lack of available information about its medical properties and gave erroneous information to the society propagating a lot of myths. Therefore, the aim of this paper is to determine its taxonomic identity and to study the distribution, bark and wood anatomy of this species, and to determine its actual and historic uses, and the compilation of the information about bark pharmacology and toxicity. Its taxonomic identity is established as Mimosa tenuiflora (Willd.) Poir. (Fabaceae-Mimosoideae). It blooms and fructifies from November to June, occurring in Mexico (the states of Oaxaca and Chiapas), Guatemala, Honduras, El Salvador, Nicaragua, Panama, Colombia, Venezuela and Brazil, at altitudes of 0-1110 (-1520) m. In Mexico, it is found in dry forests, thorny thickets, Pinus and Pinus-Quercus forests, and in M. tenuiflora pure thickets, along roads and in resting or abandoned culture lands. This species has an aggregate distribution in the forests and a uniform one in the thickets. It presents a mean density of 9 individuals per m2, with 0.45 of frequency per quadrat and 1.69 m2 of mean coverture, and it has a wide range of tolerance to climatic and edaphic factors, confirming their invasive character. Regionally, the wood is used as fuel and fence construction, and against skin wounds and burns (bark tea, powder and/or ointment), and diverse products, such as shampoos, creams, capsules, soaps, etc., are commercialized. The bark is wrinkled, reddish-brown to grey, fibrous texture, 0.5-1.5 mm thick, resinous and with an astringent odor and flavor, and with a great quantity of tannins. The wood presents extremely short vessel elements, with alternate areolate punctuations, and simple perforated plates, vasicentric axial parenchima, confluent stripes, uniseriated rays, extremely short, fine and very short libriform fibres. The bark contains tannins, saponins, an alkaloide fraction, lipids, phytosterols, glucosides, xylose, rhamnose, arabinose, lupeol, methoxychalcones, and kukulkanins.  相似文献   

15.
鄱阳湖国家级自然保护区浮游生物群落结构及空间分布   总被引:1,自引:0,他引:1  
&#  &#  &#  &#  &#  &#  &#  &#  &#  &#  &#  &#  &#  &#  &#  &#  &# 《水生生物学报》2014,38(1):158-165
为评价春季大旱后鄱阳湖国家级自然保护区浮游生物现状,对保护区所辖 8 个子湖及赣江和修河部分河段的浮游生物进行调查和分析。调查共发现浮游植物 53 属 97 种、浮游动物 23 属 42 种(包括原生动物 13 种、轮虫 23 种、枝角类 3 种和桡足类 3 种),其中大湖池和朱市湖是浮游生物种类数最多的 2 个子湖。各子湖及赣江和修河间浮游生物现存量差异较大,其变化范围分别为260(8.18106)cells/L(浮游植物)、363073173 ind./L(浮游动物),赣江以西区域的子湖和修河的浮游生物现存量显著高于赣江及其以东区域的子湖。调查水域优势度值(Y)大于 0.02 的浮游生物包括蓝藻 1 种、绿藻 2 种、硅藻 5 种、原生动物 4 种及轮虫 5 种。浮游生物 Shannon-Wiener 多样性指数(H')和均匀度指数(J)的最大值均分别为 2.41 和 0.96,而其丰富度指数(Dm)值均小于 3。3 种多样性指数综合评价表明,保护区各子湖与修河和赣江水体受污染程度较轻,除蚌湖和梅西湖外,均处于中污状态。    相似文献   

16.
城市生活垃圾代谢的研究进展   总被引:2,自引:0,他引:2  
城市代谢是导致城市发展、能量生产和废物排放的社会、经济和技术过程的总和。生活垃圾管理系统是一类典型的、具备社会、经济、自然要素的复杂系统,它不仅同管理体制、技术水平和居民素质有关,也贯穿生产、消费、流通、还原过程,更和水体、土壤、大气、生物、矿产等自然环境紧密联系。综述了近年来基于城市生态系统代谢思路,在生活垃圾碳、重金属、营养元素和能量的城市代谢等方面的研究进展,分析了未来该领域研究需重点关注的方向。生活垃圾在城市生态系统中的能量流动、物质循环、代谢效率等方面的研究,可为生活垃圾管理系统的评价、规划、工程、管理研究提供科学基础。  相似文献   

17.
Fermentation has been applied to many areas of human life, including industrial production, sewage treatment, and environment management. By understanding the process and mechanism of fermentation, more comprehensive and profound cognition of the fermentation may be established to lay a foundation for our further research. In this review, we present a brief summary of recent research about fermentation and microorganisms in different territories, including foods, environment, and human health. According to the growth characteristics of different stages of microorganisms, we introduced a series of metabolic changes, fermentation mechanism, and regulation methods and how the enzymes were transported out of the cell. With further understanding and utilization of microorganisms, food can produce better flavor, nutrition, and functional metabolites through fermentation. Fermentation is also used in other industries, such as wastewater and garbage disposal, environment, and soil management. The human gut flora, in particular, has begun to receive more attention. The profound influence of microorganism on human health cannot to be underestimated. It has become a hot research area in recent years. We can get the metabolites we want by controlling the rate of fermentation and regulate the direction of fermentation. As one of the important components of modern biotechnology, fermentation engineering has been widely used in areas including food, pharmaceutical, energy, chemical industries, and environmental protection. The development of genetic engineering has brought new vitality to fermentation engineering. The application of modernization, automation and artificial intelligence technology also opens up new space for fermentation engineering. In addition, research on the understanding and regulation of metabolic mechanism has further developed the fermentation function of microorganisms.  相似文献   

18.
金建华 《生态学报》2005,25(4):676-681
红树科植物化石种类有红树属Rhizophora、秋茄属K andelia、角果木属Ceriops和木榄属Bruguiera等4属,主要分布于亚洲、欧洲、非洲、大洋洲和美洲的古新世至全新世地层中。红树科植物化石记录显示:该科植物很可能于古新世至始新世早期起源于环特提斯海沿岸,中始新世开始从这一起源中心迅速向世界其它地方包括亚洲、欧洲、非洲、大洋洲和美洲等地扩散;渐新世在上述地区继续这一扩散历程,但在欧洲的化石记录消失;中新世时在亚洲、非洲、大洋洲和美洲达到了极盛期;上新世开始分布范围有所缩小,更新世则进一步缩小;一直到全新世才又重新繁盛起来。红树科植物的这一分布格局和地史演变是与地质时期大陆漂移、洋底扩张、第四纪冰川活动、古气候和古地理的变迁紧密相连的  相似文献   

19.
城市物质代谢的生态效率——以深圳市为例   总被引:4,自引:0,他引:4  
张妍  杨志峰 《生态学报》2007,27(8):3124-3131
城市可持续发展研究的关键是城市物质代谢通量及其效率研究,但物质代谢通量仅能反映代谢速率,而其生态效率则能反映支持社会经济发展的物质代谢能力。从工业、生活的源头循环(减少原生资源的消耗)和末端循环(减少污染物的产生)角度,构建城市物质代谢生态效率的度量模型,并依据中国城市化发展进程,选定深圳市作为研究区,核算城市水、能量和废物代谢通量以及代谢的生态效率。结果表明:随着深圳市社会经济的快速发展,水、能源和废物代谢通量呈现出增长势头,但代谢的生态效率不断提高。1998~2004年间,GDP增长2.7倍,城市水和电的代谢通量分别增长1.5倍和3.0倍;工业增加值增长3.7倍,工业水、电、能源和废物的代谢通量分别增长1.9、3.5、2.7倍和2.0倍;常住人口增长1.5倍,居民水和电的代谢通量分别增长1.8倍和1.7倍;资源效率提高1.8倍,环境效率提高3.7倍,生态效率提高2.3倍。虽然深圳市物质代谢的生态效率在提高,但是随着物质资源的日益稀缺,物质代谢的生态效率仍需进一步提高,而提高城市物质代谢生态效率的关键是资源效率和环境效率的协同发展,以及逐步构建废物资源化的循环链条。  相似文献   

20.
Osteoclastogenesis and osteoblastogenesis, the balancing acts for optimal bone health, are under the regulation of small guanosine triphosphate-binding proteins (GTPases) including Ras, Rac, Rho and Rab. The activities of GTPases require post-translational modification with mevalonate-derived prenyl pyrophosphates. Mevalonate deprivation induced by competitive inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase (e.g., statins) prevents the activation of GTPases, suppresses the expression of the receptor for activation of nuclear factor kappa B (NFκB) ligand (RANKL) and activation of NFκB and, consequently, inhibits osteoclast differentiation and induces osteoclast apoptosis. In contrast, statin-mediated inactivation of GTPases enhances alkaline phosphatase activity and the expression of bone morphogenetic protein-2, vascular epithelial growth factor, and osteocalcin in osteoblasts and induces osteoblast proliferation and differentiation. Animal studies show that statins inhibit bone resorption and increase bone formation. The anabolic effect of statins and other mevalonate pathway-suppressive pharmaceuticals resembles the anti-osteoclastogenic and bone-protective activities conferred by dietary isoprenoids, secondary products of plant mevalonate metabolism. The tocotrienols, vitamin E molecules with HMG CoA reductase-suppressive activity, induce mevalonate deprivation and concomitantly suppress the expression of RANKL and cyclooxygenase-2, the production of prostaglandin E2 and the activation of NFκB. Accordingly, tocotrienols inhibit osteoclast differentiation and induce osteoclast apoptosis, impacts reminiscent of those of statins. In vivo studies confirm the bone protective activity of tocotrienols at nontoxic doses. Blends of tocotrienols, statins and isoprenoids widely found in fruits, vegetables, grains, herbs, spices, and essential oils may synergistically suppress osteoclastogenesis while promoting osteoblastogenesis, offering a novel approach to bone health that warrants clinical studies.  相似文献   

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