土壤铅镉铬暴露下赤子爱胜蚓的回避行为和急性毒性

为了评价土壤重金属污染的生态毒理学效应,根据OECD(经济合作与发展组织)试验指南,研究了人工土壤中Pb、Cd、Cr暴露下赤子爱胜蚓(Eisenia fetida)的回避行为和急性毒性. 回避试验结果表明:赤子爱胜蚓产生完全回避反应的土壤w(Pb)、w(Cd)、w(Cr)分别为2 000、120、120 mg/kg. 急性毒性试验的结果表明,土壤Pb、Cd、Cr对赤子爱胜蚓14 d LD₅₀(半数致死浓度)的分别为2 526.05、362.83、229.44 mg/kg. 在检测Pb、Cd和Cr污染土壤时,赤子爱胜蚓回避试验的灵敏度要高于急性毒性试验. 该研究结果揭示出,赤子爱胜蚓的回避行为指标能够成为土壤生态系统风险评价和毒性效应研究的生物标志物预警指标.      

Microbial indicators of heavy metal contamination in urban and rural soils

Urban soils and especially their microbiology have been a neglected area of study. In this paper, we report on microbial properties of urban soils compared to rural soils of similar lithogenic origin in the vicinity of Aberdeen city. Significant differences in basal respiration rates, microbial biomass and ecophysiological parameters were found in urban soils compared to rural soils. Analysis of community level physiological profiles (CLPP) of micro-organisms showed they consumed C sources faster in urban soils to maintain the same level activity as those in rural soils. Cu, Pb, Zn and Ni were the principal elements that had accumulated in urban soils compared with their rural counterparts with Pb being the most significant metal to distinguish urban soils from rural soils. Sequential extraction showed the final residue after extraction was normally the highest proportion except for Pb, for which the hydroxylamine-hydrochloride extractable Pb was the largest part. Acetic acid extractable fraction of Cd, Cu, Ni, Pb and Zn were higher in urban soils and aqua regia extractable fraction were lower suggesting an elevated availability of heavy metals in urban soils. Correlation analyses between different microbial indicators (basal respiration, biomass-C, and sole C source tests) and heavy metal fractions indicated that basal respiration was negatively correlated with soil Cd, Cu, Ni and Zn inputs while soil microbial biomass was only significantly correlated with Pb. However, both exchangeable and iron- and manganese-bound Ni fractions were mostly responsible for shift of the soil microbial community level physiological profiles (sole C source tests). These data suggest soil microbial indicators can be useful indicators of pollutant heavy metal stress on the health of urban soils.     

紫茎泽兰与伴生植物小藜的竞争效应及其生理生化特征

外来入侵物种紫茎泽兰（Ageratina adenophora Sprengel）是一种世界性入侵杂草,其与本地物种的竞争会对生态系统结构和演替造成严重影响,带来较大经济损失;拟通过分析紫茎泽兰与本地物种小藜的竞争效应及生理生化特征,以探讨外来入侵物种紫茎泽兰的竞争机理。在温室条件下,设置紫茎泽兰、小藜（Chenopodium serotinum）的种内和种间竞争盆栽试验,测定了两种植物不同处理下的植株生物量;并通过氮蓝四唑光化还原法、紫外吸收法、三氯乙酸法和酸性茚三酮法,分别测定了功能叶片的超氧化物歧化酶活性、过氧化氢酶活性、丙二醛含量、脯氨酸含量。结果表明：紫茎泽兰与小藜混种时,紫茎泽兰的单株生物量、相对产量（RY）均显著高于小藜对应指标,其竞争平衡指数（CB）显著大于0,而相对产量总和（RYT）显著小于1。混种与单种的结果比较表明,紫茎泽兰的混种生物量比在单种时显著增高,增幅达22.01%;而小藜的混种生物量比在单种时显著降低,降低了44.81%。在混种中,紫茎泽兰功能叶片的丙二醛、脯氨酸含量均比在单种时显著降低,而超氧化物歧化酶、过氧化氢酶活性均比在单种时显著升高;小藜功能叶片的丙二醛含量显著高于单种,而脯氨酸含量、超氧化物歧化酶活性、过氧化氢酶活性与单种无显著变化。这说明紫茎泽兰的相对竞争能力比小藜强,紫茎泽兰通过调整生理生化特征来应对种间竞争可能是其竞争取胜的重要策略。     

Response of mussel Brachidontes variabilis to chlorination

Brachidontes variabilis is a common fouling mussel species in cooling water systems of tropical coastal power stations. However, there are hardly any data available on the response of B. variabilis to chlorine, a commonly used antifouling biocide. Therefore, lethal and sublethal responses of this mussel to chlorine are of considerable interest to the industry. The response of mussels in terms of mortality pattern (LT₅₀ and LT₁₀₀) and physiological activities (oxygen consumption, filtration rate, foot activity and byssus thread production) in different size groups (with shell lengths of 7–24 mm) of B. variabilis was studied in the laboratory under different chlorine concentrations (0.25, 0.50, 0.75 and 1.00 mg l^?1 for sublethal responses and 1, 2, 3 and 5 mg l^?1 for mortality). The results showed that the exposure time for 100% mortality of mussels decreased significantly with increasing chlorine concentration. However, mussel size was not a determinant of its chlorine tolerance: all size groups tested (with shell lengths of 7–24 mm) took comparable exposure times to reach 100% mortality at a given chlorine concentration (1–5 mg l^?1). All size groups of B. variabilis showed a progressive reduction in physiological activities such as oxygen consumption, filtration rate, foot activity and byssus thread production, when chlorine residuals were increased from 0 to 1 mg l^?1. The data generated in the present work are compared with similar data available for other tropical fouling mussel species to see how far relative chlorine toxicity could have influenced the relative distribution of the mussels inside the seawater intake tunnel of a power station at Kalpakkam in India. It is shown that in this insufficiently chlorinated system, the relative distribution of Brachidontes striatulus, B. variabilis and Modiolus philippinarum reflects the relative tolerance of the species to chlorine.     

不同光环境下薇甘菊形态和生理可塑性及其响应研究

研究了华南地区外来入侵种薇甘菊Mikania micrantha H B Kunth不同光环境下形态和生理可塑性及其适应性响应。通过模拟开阔地段、林缘、大林窗、小林窗、林下等不同生境的的光照环境,并设计一个干扰实验,分析了薇甘菊的生长、碳同化以及生物量分配如何对光环境作出适应性响应。研究了当干扰发生时,薇甘菊如何对光环境的变化做出形态和生理可塑性响应。通过对其各项生物量分配及气体交换等指标的观测,在小林窗光照环境下薇甘菊生长缓慢生物量积累较少,但是如果一旦受到干扰,光照环境得到改善,薇甘菊将在很短的时间内通过适应性形态和生理可塑性响应,迅速体现出较强的入侵性。这也可能是入侵植物薇甘菊＂坐待对策（sit and wait strategy）＂的生动体现：如果外界环境不利,暂且先保持繁殖体（种子或者根茎）,一旦条件成熟（发生干扰条件得到改善或者遗传变异或者生态生理的积累）,就会迅速爆发。所以我们一方面,不用担心郁闭的森林会被薇甘菊入侵,但另一方面也要注意干扰会引起光照等环境条件的改变,使得原来潜伏于林下的薇甘菊繁殖体重新变得富有入侵性。     

Selecting agri-environmental indicators to facilitate monitoring and assessment of EU agri-environmental measures effectiveness

Since its introduction in the early 1960s, the EU Common Agricultural Policy (CAP) has demonstrated a capacity to adapt and change in the face of new challenges. The reformed CAP, under AGENDA 2000, encourages more environmentally friendly farming practices. In the context of their rural development plans, Member States are required to link policies on agriculture with protection of the environment and to ensure that farmers meet environmental standards. Additionally, Member States should maintain and restore the quality of both their aquatic and adjacent terrestrial ecosystems according to the Directive 2000/60/EU, 'Establishing a framework for Community Action in the field of Water Policy'. Within this framework, agri-environmental indicators play an important role in planning and implementing CAP guidelines. However, selection and use of the proper indicators remains unresolved, considering that ecosystem processes are complex and interactions in most cases not obvious. This paper proposes a methodology for assessing the environmental state and impacts of current land use and management when implementing agri-environmental measures of CAP. The proposed methodology includes a modified Driving forces-Pressures-Impacts-Responses (DPSIR) framework, identification of Zones of Specific Functional Interest (ZSFI), and criteria for selecting agri-environmental indicators, which assess the functional performance of each zone and meet existing legislation. The Mygdonia Watershed (Greece) is an example where through use of both the appropriate Minimum Data Set of agri-environmental indicators at the identified zones and the proposed modified DPSIR, the functioning performance of each ZSFI can be assessed to evaluate the applied agri-environmental measures.     

Common volatiles are major attractants for neonate larvae of the specialist flea beetle <Emphasis Type="Italic">Altica koreana</Emphasis> (Coleoptera: Chrysomelidae)

Olfactory stimuli play an important role in the host searching of larval phytophagous insects. Previous studies indicate that larvae that have to find feeding sites after hatching are generally attracted to host volatiles. However, there are few studies on the olfactory responses of neonate larvae to host volatiles in cases when those larvae hatched on the host plant. In the present study, we determined the olfactory responses of neonate larvae of the specialist flea beetle, Altica koreana Ogloblin, to host and six non-host plants, using a static-air "arena." Larvae responded significantly to the host plant Potentilla chinensis Ser. and five of six non-host plants, compared to the control. Larvae did not prefer the host plant over the non-host plants (except Artemisia sp.) when offered a choice. Additionally, odours of a non-host plant, which were unattractive to neonate larvae, may have masked the attractive odour of the host plant. These results indicate that common volatiles can play a major role in attracting larvae of this specialist to plants, but attraction to such odours may not be the major mechanism of host choice.     

考虑刚体响应的多层响应谱抗震分析

目的研究刚体响应对多层响应谱抗震分析结果的影响。方法使用ANSYS15.0对某核电设备进行多层反应谱抗震分析,并对考虑刚体响应和未考虑刚体响应的计算结果进行对比分析。结果考虑刚体响应对不同标高约束处预埋板的基础载荷影响不同,且对部分标高的影响可能较大。结论对类似的核电设备进行多层响应谱抗震分析时,应注意考虑刚体响应的影响。     

Research progress and prospects of complete ammonia oxidizing bacteria in wastewater treatment

• Comammox bacteria have unique physiological characteristics. • Comammox bacteria are widely distributed in natural and artificial systems. • Comammox bacteria have the potential to reduce N₂O emissions. • Coupling comammox bacteria with DEAMOX can be promoted in wastewater treatment. • Comammox bacteria have significant potential for enhancing total nitrogen removal. Complete ammonia oxidizing bacteria, or comammox bacteria (CAOB), can oxidize ammonium to nitrate on its own. Its discovery revolutionized our understanding of biological nitrification, and its distribution in both natural and artificial systems has enabled a reevaluation of the relative contribution of microorganisms to the nitrogen cycle. Its wide distribution, adaptation to oligotrophic medium, and diverse metabolic pathways, means extensive research on CAOB and its application in water treatment can be promoted. Furthermore, the energy-saving characteristics of high oxygen affinity and low sludge production may also become frontier directions for wastewater treatment. This paper provides an overview of the discovery and environmental distribution of CAOB, as well as the physiological characteristics of the microorganisms, such as nutrient medium, environmental factors, enzymes, and metabolism, focusing on future research and the application of CAOB in wastewater treatment. Further research should be carried out on the physiological characteristics of CAOB, to analyze its ecological niche and impact factors, and explore its application potential in wastewater treatment nitrogen cycle improvement.     

五种亚热带树苗的生长与干物质分配格局对大气污染胁迫的响应

将乡土木本植物猫尾木Dolichandronecauda-felina、蒲桃Syzygiumjambos、野牡丹Melastomacandidum、翻白叶树Pterospermumheterophyllum以及鸭脚木Scheffleraoctophylla1年生袋装苗盆栽,置半庇荫环境下适应4周,之后按株数均等分成两组,分别放置在南海五星污染区和广州华南植物园清洁区进行试验。5个月后进行植物构形生长参数和干物质量的测定,以探讨这5种亚热带树苗对大气污染响应的差异。结果表明,①这5种树苗均能在清洁区和污染区都存活,但生长特征表现明显差别。②除翻白叶树基径有少许增大外,大气污染基本上都使植物基径生长减小;树高方面,除了蒲桃外,其余树种树高都有所降低,鸭脚木树高受到的影响最为严重。③翻白叶树与猫尾木单株侧枝数有少许增加,而蒲桃和鸭脚木单株侧枝数有大幅度地下降,分别减少为清洁区单株侧枝数的46.5%和65.1%,野牡丹单株侧枝数基本上没有受到影响。④在污染区生长的5个树种单株干物质总量除了翻白叶树有所增加外,其余4个树种单株干物质量均有不同程度地下降。⑤除了蒲桃保持不变外,污染区?生长4种植物冠根比(CRR)均有不同程度地增加。在污染区生长的植株叶质量比(LWR)和叶面积比(LAR)与清洁区相比存在差异,野牡丹和蒲桃叶质量比和叶面积比下降,而其余3种植物叶质量比和叶面积比上升。综合实验结果表明,5种植物幼苗中对大气污染抗性最强的是翻白叶树和蒲桃,抗性最弱的是鸭脚木。