塔里木河干流农田排水资源化研究

近几十年经表明，农田排水对塔里木河干流水质盐化的影响不断加重。在塔里木河干流，农田排水资源化利用有如下几个有利条件：⑴农田排水有一定数量且渠网的延伸和改造难度不大；⑵荒漠可作为农田排水资源化利用的场所；⑶农田排水仍可勉强适于耐盐植物生长。根据区域不同利用农田排水拓展乔灌草防沙带、增加盐成土荒漠耐盐植被的盖度、使人工绿洲边缘的荒漠能够生长耐盐植物等都是农田排水资源化利用发展的方向。     

高盐污水处理人工湿地中耐盐植物的筛选

人工湿地作为一种新兴污水处理工艺,具有高效、低成本等优点,但因缺乏能够在高盐环境中生存的湿地植物,因此应用于高盐污水处理还存在诸多难题.基于对我国南方海岸及海岛的大量野外调查及文献调研,依据生理指标、形态指标、经济成本和应用潜力等,筛选出耐盐、耐水湿、耐污、净化能力强、生长快、生物量大、栽培简单、分布广泛并具有景观效果的南方滨海耐盐植物23种,进一步对每一种植物的耐盐能力进行分级,其中耐盐能力最强的种类为扁秆荆三棱(Bolboschoenus planiculmis)、海雀稗(Paspalum vaginatum)、川蔓藻(Ruppia maritima)、海马齿(Sesuvium portulacastrum)和盐地碱蓬(Suaeda salsa).本研究结果可为人工湿地的构建提供更多植物种类选择,并促进人工湿地可持续的净化功能与景观功能的有机结合.     

中新天津生态城植物多样性分析

2008年对中新天津生态城规划区域植被进行调查,发现该区域以盐生植被为主,现存植被可分为4个类型15种植物群落;植物区系成分含38科101属135种。本区植被的分布受土壤盐碱度的制约,并受当代人为因素的严重影响,盐生植物资源丰富,其中26种耐盐植物具有较大开发利用价值。因此,建议采取保留与保护现存的盐生植被;利用耐盐植物进行盐碱地绿化及研究和发展本区盐碱地环境的生态管理。     

植物耐盐研究概况与展望

概述了植物耐盐性有关领域的研究进展，包括环境因素对植物耐盐性影响、植物耐盐种质资源评价、植物耐盐的生理生化基础、植物耐盐分子生物学和耐盐植物的开发利用等5个方面。同时对植物耐盐性研究的意义和展望进行了简要探讨。     

吉兰泰盐湖周边荒漠植物养分、叶片功能性状及适应策略研究

为分析叶片功能性状与养分质量分数的相关关系,探究荒漠植物通过叶片功能性状、养分特征表现出的对环境胁迫的适应策略,以阿拉善盟吉兰泰盐湖区固定沙地生长的荒漠植物为研究对象,对植物叶片的水分与功能性状指标、养分元素质量分数进行测定,运用单因素方差分析、相关性分析等方法对叶片功能性状、养分质量分数以及二者的关系进行分析。结果表明,(1)荒漠植物通过较高的干物质质量分数(LDMC,0.125—0.329 g·g~(-1))、较低的比叶面积(SLA,1.071—23.291 m2·kg~(-1))和叶片含水量(LWC,53.271%—87.102%)来抵御荒漠环境的胁迫,可将这3个指标结合作为荒漠植物筛选的主要性状指标。(2)通过与其他相关研究结果对比,得出荒漠植物叶片通过高水平的N、K、Mg、Na质量分数进行调节,提高植物对水分的利用效率,保证正常生理功能。不同种植物生长受N、P限制的表现不同。(3)荒漠植物通过较高的叶片N、P质量分数来满足植物生长对养分的需要,比叶面积与N质量分数呈正相关,比叶面积高的植物生长速率高,易取得竞争优势;N、P、Na质量分数与叶片干物质质量分数呈极显著负相关,而与叶片含水量呈正相关;Ca、Mg、Na的质量分数与叶片相对含水量和叶片厚度均呈显著正相关关系,Ca、Mg、Na作为植物叶片细胞稳定性及渗透压调节元素在发挥作用。     

对我国农业废弃物资源化利用的思考

对我国农业废弃物的资源化利用状况进行了综述分析与探讨,指出当前我国在农业废弃物利用方面尚存在诸多问题,包括农业废弃物产生量巨大且总量不清、农业废弃物粗放低效利用且闲置状况严重、农业废弃物利用技术与产业化水平滞后,以及农业废弃物利用相关的政策法规与社会化服务体系不健全等问题,同时,总结指出了我国农业废弃物资源化利用的几个发展方向,即向能源化、肥料化、饲料化、材料化、基质化和生态化发展.在此基础上提出了我国农业废弃物资源化发展的对策措施,包括:(1)建立与健全农业废弃物资源化利用与无害化处理相关的政策法规;(2)结合新农村建设,加大资金扶持力度,加强农业废弃物利用的基础设施建设;(3)加快推动农业废弃物资源化利用的产业化进程,大力发展循环经济;(4)鼓励和推动农业废弃物资源化利用技术的创新研究、示范与推广工作.     

宁夏东北部典型荒漠草原植物群落与土壤养分特征

以宁夏东北部荒漠草原为研究区,采用野外样方调查、采样和室内植物鉴定、土壤样品测定等方法,探析研究区内植物群落物种组成与土壤养分特征,以及植物多样性指数与土壤养分的相关关系,以期为中国荒漠治理、生物资源保护与可持续性利用提供依据。结果显示:(1)研究区植物共86种,隶属61属21科,其中禾本科(18种)、豆科(16种)、菊科(13种)和藜科(11种)植物占总物种数的67.44%;(2)研究区土壤总体上呈碱性,pH值平均为8.81,全氮、全磷、有机质的质量分数(0-10 cm土层)分别为0.07-0.54、0.16-0.51、0.51-6.24 g·kg^-1;(3)研究区植物多样性指数中的Margalef丰富度指数和Shannon-Wiener多样性指数与土壤pH值呈显著负相关,与其他土壤养分的相关关系未达到显著水平,其他植物多样性指数与土壤养分的关系均未达到显著水平。研究表明,宁夏东北部荒漠草原植物种类少,禾本科、豆科植物优势明显,土壤养分条件差,土壤全氮、全磷、有机质对植物多样性指数的影响不大。     

塔里木河下游生态输水过程中荒漠河岸林活力恢复监测

根据近5年来对塔里木河下游荒漠河岸林植被的监测数据,分析了生态输水后植物活力的恢复状况.结果显示:应急生态输水增加了塔里木河下游的生物多样性,使原本面临死亡的荒漠河岸植被重新复活,而且不同程度上促进了胡杨群落的自然更新;在近河道50 m的范围内均出现了少量的胡杨、柽柳实生苗,并且在离河道150 m的范围内已经有相当数量的胡杨次生苗,在离河道400 m范围内大约有25%的胡杨均有不同程度的基部新枝萌蘖.通过生态输水后地下水位的逐步抬升,河道两岸的低阶地发育着一定面积的草甸植被,形成了由胡杨、柽柳和草本植物所组成的干旱区非地带性河岸稀疏植被群落,说明应急生态输水对于胡杨为建群种的荒漠河岸林植被的恢复和自然更新产生了积极的影响.     

几种植物在生长过程中对人工湿地污水处理效果的影响

不同的植物及植物的不同生长阶段对人工湿地系统污水处理效果都有影响。对几种华南地区常见的湿地植物在其不同生长阶段处理污水的效果进行了研究,采用了不种植物的沙滤系统作对照。结果表明:(1)植物生长过程中,植物高度能反映污水处理效果总体上的变化;(2)在植物的生长过程中,各人工湿地系统污水处理能力总体上持续增强,各水质指标pH、DO、TN、NH3-N、NO3-N、TP和CODCr等均呈下降趋势,其中TP和CODCr呈逐步下降,pH、DO、TN、NH3-N、NO3-N则呈现锯齿形波动,但总体上仍是下降过程;(3)植物系统氮处理能力好于无植物沙滤系统,而对磷TP和CODCr的去除则恰好相反;(4)不同植物对人工湿地污水的处理效果影响不明显。研究结果对探讨人工湿地污水处理规律和植物在人工湿地中的作用提供了新的科学依据,并为指导人工湿地工程的运行提供了参考。     

丛枝菌根-植物修复重金属污染土壤研究中的热点

随着菌根研究和植物修复技术的发展,利用丛枝菌根强化重金属污染土壤的植物修复逐渐受到人们的重视。本文系统综述了当前的几个研究热点:(1)菌根植物吸收和转运重金属的分子机制;(2)AM真菌对超富集植物重金属吸收的影响及其机制;(3)AM真菌对转基因植物重金属吸收的影响及其机制;(4)AM真菌与其他土壤生物在植物修复中的复合作用;(5)丛枝菌根与化学螯合剂在植物修复中的复合作用;(6)重金属复合污染土壤的丛枝菌根-植物修复;(7)放射性污染土壤的枝菌根-植物修复;(8)丛枝菌根-植物修复的田间试验研究。在未来的丛枝菌根-植物修复研究中,要筛选优良的宿主植物和与之高效共生的AM真菌,加强相关理论和应用基础研究,并构建高效基因工程菌。     

Age-specific responses to elevated salinity in the coastal marsh plant black needlerush (Juncus roemerianus Scheele) as determined through polyphasic chlorophyll a fluorescence transients (OJIP)

This study employed polyphasic chlorophyll a fluorescence transients (OJIP), a non-invasive marker of environmental stress in plants, to evaluate salt tolerance in three different Juncus roemerianus age classifications (6-, 24-, and 60-months). Following exposure to elevated salts (30 psu), the younger plants sustained growth, which was comparable to freshwater controls. While older (60-month) plants receiving only freshwater also grew over the 8-week study, the older salt-treated plants did not increase in size. Similarly, there were significant declines in variable chlorophyll a fluorescence parameters (F _v/F _m and F _v/F _o), electron transport flux per reaction center (ET_o/RC), and photosystem II performance index (PI_ABS) for 60-month J. roemerianus following salt treatment. These responses were not evident in the two younger salt-treated age classifications. Our results suggest that older J. roemerianus are less tolerant to rapid and sudden increases in salinity relative to younger plants and that this age-specific response may help explain observed discrepancies in salt tolerance in J. roemerianus.     

The impact of gasoline emission on plants – a review

This review presents the status of knowledge about gasoline exhaust pollution and its impact biochemical and physiological characteristics of plants. Parameters on such as leaf conductance, membrane permeability, ascorbic acid, chlorophyll and relative water content have been used as indicators to assess the impact of gasoline exhaust pollution on plant health. Tolerant plants such as Mangifera indica Linn. are reported showing an insignificant decrease in the percentage of chlorophyll content (3.6%) and a significant increase in the percentage of ascorbic acid (84.6%) and sensitive plants such as Cassia fistula are reported showing a significant decrease in the percentage of chlorophyll (66.4%) as well as ascorbic acid (32.9%). In the case of ornamental plants, Dracaena deremensis has been reported to show an insignificant decrease in the chlorophyll content but a significant increase in the ascorbic acid, pH and relative water content, which were found to be in tolerant category, while Dianthus caryophyllus showed sensitive characteristics. Such plants can be used as sinks and bioindicators for gasoline exhaust pollution. Though several studies reported biochemical impacts of individual or combined exhaust gases on plant species, the cumulative effect of gasoline exhaust on plant species has not been studied extensively, especially in the developing countries.     

Coupling soil water and shoot dynamics in three grass species: A spatial stochastic model on water competition in Neotropical savanna

Savannas are ecosystems known for their high environmental and economic value. They cover at least 20% of the global land surface and, in some cases, can act as a boundary between tropical rainforest and deserts. Water is an important determinant of savanna ecosystems.In this paper, we present a theoretical stochastic model of root competition for water, which couples, soil water availability, phenology, and root and shoot architecture applied to three Neotropical savanna grasses. Soil moisture was simulated using a daily balance, as proposed by Rodriguez-Iturbe et al. [Rodriguez-Iturbe, I., Porporato, A., Ridolfi, L., Isham, V., Cox, D.R., 1999. Probabilistic modelling of water balance at a point: the role of climate, soil and vegetation. Proc. R. Soc. London, Ser. A 455, 3789–3805.]. To simulate rainfall stochasticity, we used daily precipitation data from the airport weather station in the State of Barinas, Venezuela, for the period 1991–2007. Competition among neighbouring plants took into account the spatial distribution of the individuals. As a final step, the model allowed us to calculate the shoot dynamic of the species as a function of soil water availability.Using these data, we compared the behaviour of isolated plants, pairs and trios, and we found below-ground competition to be a fundamental component of global (shoot + root) competition. Finally, our model suggests various circumstances that allow poor competitor plants to coexist in competition for water with more successful competitors. Apparently, this is not only due to transpiration rates, but also to differences in shoot emergence and shoot growth.     

Characterization of boron tolerant bacteria isolated from a fly ash dumping site for bacterial boron remediation

Boron is an essential micronutrient for plants, but can above certain concentrations be toxic to living organisms. A major environmental concern is the removal of boron from contaminated water and fly ash. For this purpose, the samples were collected from a fly ash dumping site, Nagasaki prefecture, Japan. The chemical characteristics and heavy metal concentration of the samples were performed by X-ray fluorescent analysis and leaching test. For bacterial analysis, samples were collected in sterile plastic sheets and isolation was carried out by serial dilution method. The boron tolerant isolates that showed values of maximum inhibitory concentration toward boron ranging from 100 to 260 mM level were screened. Based on 16S rRNA sequencing and phylogenetic analysis, the isolates were most closely related to the genera Bacillus, Lysinibacillus, Microbacterium and Ralstonia. The boron tolerance of these strains was also associated with resistant to several heavy metals, such as As (III), Cr (VI), Cd, Cu, Pb, Ni, Se (III) and Zn. Indeed, these strains were arsenic oxidizing bacteria confirmed by silver nitrate test. These strains exhibited their salt resistances ranging from 4 to 15 % were determined in Trypticase soy agar medium. The boron tolerant strains were capable of removing 0.1–2.0 and 2.7–3.7 mg l^?1 boron from the medium and fly ash at 168 h. Thus, we have successfully identified the boron tolerant and removal bacteria from a fly ash dumping site for boron remediation.     

Floristic composition of arid off –shore islands in Abu Dhabi,United Arab Emirates

Data on flora and vegetation of 14 off-shore islands representing different habitat types were studied for investigating floristic composition, vegetation types and correlation with their habitats and ecosystem. The results demonstrate considerable plant distribution and diversity among the islands within the limited spectrum of species; encompassing a total of 47 species, belonging to 43 genera under 24 families. The most representative families were Amaranthaceae (9 species), Fabaceae (4 species), Poaceae (4 species) and Asteraceae and Aizoaceae (3 species each). Fourteen families are represented by only one species. The mangrove species, Avicennia marina, occurs throughout the coast of Abu Dhabi in discontinuous patches and in different water salinities. The studies also seek to underline that dominant species that constitutes the flora of Abu Dhabi are salt tolerant in nature. Compared to other Arabian Peninsula ecosystems, UAE perhaps has a higher coastal: mainland area ratio, which has contributed to a natural dominance of salt tolerant species among the community. The studies show 40% similarity among islands with respect to the species diversity. The floristic composition of the off-shore islands also indicates a need to consider these sites as protected sites.     

Risk Assessment of Riparian Plant Invasions into Protected Areas

Abstract:  Protected areas are becoming increasingly isolated. River corridors represent crucial links to the surrounding landscape but are also major conduits for invasion of alien species. We developed a framework to assess the risk that alien plants in watersheds adjacent to a protected area will invade the protected area along rivers. The framework combines species- and landscape-level approaches and has five key components: (1) definition of the geographical area of interest, (2) delineation of the domain into ecologically meaningful zones, (3) identification of the appropriate landscape units, (4) categorization of alien species and mapping of their distribution and abundance, and (5) definition of management options. The framework guides the determination of species distribution and abundance through successive, easily followed steps, providing the means for the assessment of areas of concern. We applied the framework to Kruger National Park (KNP) in South Africa. We recorded 231 invasive alien plant species (of which 79 were major invaders) in the domain. The KNP is facing increasing pressure from alien species in the upper regions of the drainage areas of neighboring watersheds. On the basis of the climatic modeling, we showed that most major riparian invaders have the ability to spread across the KNP should they be transported down the rivers. With this information, KNP managers can identify areas for proactive intervention, monitoring, and resource allocation. Even for a very large protected area such as the KNP, sustainable management of biodiversity will depend heavily on the response of land managers upstream managing alien plants. We suggest that this framework is applicable to plants and other passively dispersed species that invade protected areas situated at the end of a drainage basin.     

A neutral DNA marker suggests that parallel physiological adaptations to open shore and salt marsh habitats have evolved more than once within two different species of gastropods

Local adaptation is an important mechanism generating physiological diversity and can be especially pronounced in species with restricted dispersal and gene flow such as direct developing snails of the genus Littorina. We compared physiological responses to salinity and desiccation stress in two co-occurring species of northeastern Pacific Littorina (L. subrotundata and L. sitkana) with salt marsh and open shore ecotypes. The animals from salt marsh populations were significantly more tolerant to low salinities and significantly less resistant to desiccation stress than their open shore counterparts. The lower resistance to desiccation in salt marsh animals was not associated with a higher rate of water loss during air exposure or with lower body water reserves, but instead reflected a lower tolerance to high salinities. These habitat-related physiological differences occurred in parallel in the two studied species of Littorina and persisted after prolonged laboratory acclimation, suggesting that they may reflect selection for markedly different local optima in the salt marsh habitats than in the open shore habitats. We used a neutral polymorphic nuclear DNA marker (intron of aminopeptidase N) to estimate the level of gene flow between the populations from different habitats and found isolation by distance regardless of the habitat from which the snails were collected. Our molecular data suggest that physiological cohesiveness of ecotypes can arise despite different genetic backgrounds, and could potentially be due to parallel evolution of convergent phenotypes in similar habitats.Communicated by O. Kinne, Oldendorf/Luhe     

Land Forms and Winter Habitat Refugia in the Conservation of Montane Grasshoppers in Southern Africa

Abstract: The importance of topography in evaluation of insect conservation is discussed with reference to grasshoppers in the Natal Drakensberg Mountains, South Africa For these insects, the hilltops act as thermal refugia from winter cold air drainage. Additionally, the increased insolation on the eastern and northern sides of the hilltops, compared with the western and southern sides, attracts the grasshoppers. Crevices in the hill summits provide further microrefugia Burning reduces grasshopper numbers by half and although many species are adapted to burn conditions, the reduced grass cover accentuates the thermal influences. Other animals, and plants, also selectively inhabit these hilltops, making them highly significant conservation refugia in a matrix of thermally inhospitable land. Evaluations for biological conservation should take note of the strong influence that land forms may have on plant and animal local distributions.