Monoterpene emissions from three Nothofagus species in Patagonia,Argentina

Abstract

Isoprenoid emissions have key roles in plant biology and plant interactions with the environment. Global emission inventories of isoprenoid emissions still lack information from a large number species, especially from South American vegetation other than the rainforest ecosystem. A study was conducted to identify the basal emission of isoprenoid under field conditions from three Nothofagus species. The three Nothofagus species were characterized as strong monoterpene emitters while the emission of isoprene was undetectable. The two deciduous species, N. pumilio and N. antarctica, had similar photosynthetic parameters, but monoterpene emission rate and, consequently, the fraction of photosynthetic carbon re-emitted in the atmosphere as monoterpenes, were more than three-fold higher in N. pumilio than in N. Antarctica. The evergreen species N. dombeyi showed intermediate values of both monoterpene emission rate and fraction of photosynthetic carbon re-emitted. The monoterpene emission spectrum was very similar among the three Nothofagus species screened, but clearly different from the spectrum reported in other monoterpene-emitting species of the Fagaceae family. The importance of these findings for atmospheric chemistry and phylogenic evolution are discussed.     

城市植物挥发性有机化合物排放与臭氧相互作用及其机制

近地面臭氧(O₃)已成为继PM_2.5后影响我国空气质量的一种重要二次污染物。随着氮氧化物浓度的持续下降和气候变暖的加剧,城市O₃的形成对挥发性有机化合物的浓度更加敏感。近年来城市绿色空间显著增长,植物源挥发性有机化合物(BVOCs)排放和浓度逐年增加。针对BVOCs与近地面O₃之间复杂的交互作用,从植物BVOCs的特性与作用出发,综述了不同因素尤其是O₃浓度增加对树木生理状态及BVOCs排放速率的影响,定量分析了已有研究中O₃对不同植物异戊二烯和单萜烯排放速率的影响,以及BVOCs对O₃形成的贡献,总结了BVOCs与O₃相互作用研究领域存在的不足。未来亟需加强的研究包括：(1)城市树种BVOCs排放因子的实测,建立物种的排放速率数据库,优化模型参数,提升精细尺度BVOCs排放量估算模型精度;(2)多种环境因子,比如污染物浓度、温湿度等对城市植物BVOCs排放的交互作用和综合影响的研究;(3)植物BVOCs对O     

几种海南岛热带雨林优势种植物挥发性有机物排放对模拟氮沉降的短期响应

BVOCs(Biogenic Volatile Organic Compounds)是植物向大气释放的一类重要气态化合物,能参与大气化学过程和陆地生态系统碳素循环。分析环境因子对BVOCs排放的影响,对科学认识未来气候变化具有重要意义。氮素作为植物生长、发育所需的大量营养元素之一,其沉降增加是当前全球气候变化的主要驱动因素之一,但学者对BVOCs如何应对氮沉降增加知之甚少。因此以海南岛热带雨林树种：木荷(Schima superba)、厚壳桂(Cryptocarya chinensis)和线枝蒲桃(Syzygium araiocladum)为研究对象,通过温室盆栽实验模拟氮沉降对3个树种BVOCs释放的短期效应。主要结论如下：(1)自然状态下,从木荷、厚壳桂和线枝蒲桃的枝叶中鉴定出14、34和24种挥发性有机化合物,包括异戊二烯、单萜烯、倍半萜烯和其他挥发性有机化合物(烷烃、羰基、醛、醇、酯、醚和酸),此外三个阔叶树种释放BVOCs的速率呈厚壳桂>木荷>线枝蒲桃;(2)外源施氮均促进了三种植物幼苗VOCs释放,其中总VOCs释放速率和成分数量均随施氮浓度的升高而增加,且叶面...     

城市家庭能耗直接碳排放影响因素——以厦门岛区为例

在全球城市化迅速推进的过程中,城市碳排放已经成为影响全球变化不可忽视的一部分,同时也成为制约城市可持续发展重要因素之一。家庭能耗碳排放是城市碳排放的一个组成部分,分析它的各种影响因素对于控制它对局域乃至全球气候变化的负面影响具有重要的意义。以厦门岛区为例,通过社会问卷设计和调查,应用数理统计方法对最终收回的340份有效问卷进行城市家庭能耗的影响因子分析,结果表明,2007年厦门岛区平均家庭能耗直接碳排放量为1218.2kg/(户.a),电力消耗直接碳排放是厦门岛区主要的家庭能耗直接碳排放方式,电力消耗直接碳排放量是瓶装液化石油气与代用天然气使用直接碳排放总量的近5倍。通过单因素方差分析与多元逐步回归方程得到,与住区自然环境与家庭耗能倾向相比,家庭社会情况是影响家庭能耗直接碳排放最为重要的因子,其对家庭能耗直接碳排放变化的解释能力为17.9%。通过主成分分析得到,家庭住宅面积对家庭能耗直接碳排放的影响最为显著,家庭住宅面积对公共因子的贡献率达到了0.829。研究旨在为城市节能减排和可持续发展提供第一手资料、为城市住区形态的合理设计和规划提供科学依据。     

沈阳市四种乔木树种BVOCs排放特征

采用热解析与气相色谱联用技术对沈阳市4种主要乔木树种--银中杨、垂柳、榆树和皂角的BVOCs排放特征进行了观测.实验发现,不同树种排放BVOCs的组成情况明显不同,银中杨和垂柳以释放异戊二烯为主,且二者的BVOCs排放速率明显高于其他树种;榆树和皂角以释放柠檬烯为主.4种乔木树种BVOCs的释放具有显著的日变化和季节变化规律,各树种的BVOCs排放速率日变化曲线多表现为单峰型,排放高峰一般出现在中午或下午,且夜间几乎均不排放异戊二烯.季节变化趋势主要表现为夏季最高,春、秋季较低.     

Health risk assessment of volatile organic compounds in urban areas

The atmosphere is the first medium containing hazardous compounds entering the living environment. Metropolitan areas contain many industrial complex areas with high emissions of volatile organic compounds (VOCs), and consequently also large-scale exposure groups. As respiration is the most important part of the human exposure pathway, the atmosphere should be treated with greater importance than other media. It is therefore very important to monitor the emission of hazardous air pollutants (HAPs) and measure the concentration of VOCs in the atmosphere of such areas. It is essential to establish basic measures in order to protect public health as part of overall national safety management. This study utilized the national air pollution monitoring network data from Seoul, Incheon, and Gyeonggi, and investigated the differences in risk levels for humans considering various factors of the receptors, including gender and age. A total of 13 VOCs were categorized into carcinogens and noncarcinogens for risk assessment. The carcinogens 1,3-butadiene and benzene demonstrated a high level of cancer risk, ranging between 10^?4 and 10^?6, respectively. Noncarcinogens did not exceed Hazard Quotient (HQ) 1 in any area. The results will serve as important references for managing urban air environments and setting air quality standards.     

城市花粉致敏植物种类构成、分布与潜在危害评估——以深圳市为例

气传致敏花粉会引发过敏症,且可通过每年在花粉季的反复接触逐渐加重,危害人体健康,严重时甚至危害生命。花粉致敏植物在城市中被广泛引种栽培,导致城市花粉症患者数量激增。以深圳市为案例,基于建成区600个样地的实地调查数据,分析花粉致敏植物的种类构成与时空分布,通过构建花粉浓度及花粉致敏危害潜力计算公式,评估花粉致敏危害潜力及其分布特点。结果显示：①调查记录到深圳市建成区花粉致敏植物46科92属186种,其中外来种占43.37%,其中美洲、亚洲和大洋洲来源占国外外来种的81.00%。花粉致敏植物种数以公园绿地最多,达126种。植物花粉致敏等级以Ⅰ级为主,达154种。②花粉致敏植物的盛花期为春夏季,占全年累计开花种数的65.02%。最高峰出现在8月,开花种数达92种。 ③花粉浓度潜力最高值也出现在8月,占全年总值的12.13%。豆科和禾本科植物贡献比例较大,分别占乔木和草本总值的40.86%和64.13%。龙岗区花粉浓度潜力占比较高,占各季花粉量的26.06%-29.42%。④冬春两季各样地花粉致敏危害等级均不高,但夏秋季有些样地达到二级重度危害。罗湖区调查样地全年花粉致敏危害等级均较低,光明区在春夏秋季致敏危害等级皆较高。高危害等级样地主要出现在附属绿地及公园绿地。⑤花粉致敏植物防控措施情景模拟结果,去除主要花粉致敏植物种类比降低所有花粉致敏植物的花粉浓度潜力更有效。本研究为城市花粉致敏植物的管理、规划、养护和研究提供参考。     

Tissue-specific regulation of volatile emissions moves predators from flowers to attacked leaves

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Monoterpene emissions from rubber trees (Hevea brasiliensis) in a changing landscape and climate: chemical speciation and environmental control

Emissions of biogenic volatile organic compounds (VOCs) have important roles in ecophysiology and atmospheric chemistry at a wide range of spatial and temporal scales. Tropical regions are a major global source of VOC emissions and magnitude and chemical speciation of VOC emissions are highly plant-species specific. Therefore it is important to study emissions from dominant species in tropical regions undergoing large-scale land-use change, for example, rubber plantations in South East Asia. Rubber trees ( Hevea brasiliensis ) are strong emitters of light-dependent monoterpenes. Measurements of emissions from leaves were made in the dry season in February 2003 and at the beginning of the wet season in May 2005. Major emitted compounds were sabinene, α -pinene and β -pinene, but β -ocimene and linalool also contributed significantly at low temperature and light. Cis -ocimene was emitted with a circadian course independent of photosynthetic active radiation (PAR) and temperature changes with a maximum in the middle of the day. Total isoprenoid VOC emission potential at the beginning of the wet season (94 μg gdw⁻¹ h⁻¹) was almost two orders of magnitude higher than measured in the dry season (2 μg g dw⁻¹ h⁻¹). Composition of total emissions changed with increasing temperature or PAR ramps imposed throughout a day. As well as light and temperature, there was evidence that assimilation rate was also a factor contributing to seasonal regulating emission potential of monoterpenes from rubber trees. Results presented here contribute to a better understanding of an important source of biogenic VOC associated with land-use change in tropical South East Asia.     

Coupling isoprene and monoterpene emissions from Amazonian tree species with physiological and environmental parameters using a neural network approach

The ability to predict isoprene emissions from plants is important for predicting atmospheric chemistry. To improve the basis for prediction capability, data obtained from continuous field measurements of isoprene and monoterpene emissions from three Amazonian tree species were related to observed environmental and leaf physiological parameters using a new neural network approach. The environmental parameters included leaf temperature, light, relative humidity, water vapour pressure deficit, and the history of ambient temperature and ozone concentration, whereas the physiological parameters included stomatal conductance, assimilation and intercellular CO₂ concentration. The neural approach with 24 different combinations of these parameters was applied to predict the emission variability observed during short time periods (2–3 d) with individual tree branches and, on a longer-term scale, in aggregated data sets from different seasons, leaf developmental stage, and light environment. The results were compared to the quasi standard emission algorithm for isoprene. On the short-term scale, good agreement (r²≈ 0.9) was obtained between observations and predictions of the standard algorithm as well as predictions of the neural network using the same input parameters (leaf temperature and light). When these predictors were used to model the long-term emission variability, r² was reduced to < 0.5 for both approaches. Remarkably, for the neural technique, more than 50% of the unexplained variance could be explained by the mean temperature of the preceding 36 h. An even better network performance was obtained with physiological parameter combinations (r² > 0.9) suggesting a strong and applicable link between isoprenoid emission and leaf primary metabolism.     

中国典型城市群城镇化碳排放驱动因子

城市群作为推进国家新型城镇化的战略举措,是国家参与全球竞争与国际分工的主要地域单元。以中国典型城市群6个代表性城市(北京、天津、上海、广州、武汉和重庆)为案例,采用因素分解法将碳排放的影响效应分解为4部分,包括人口规模效应、经济发展效应、能源强度效应和碳强度效应,研究2000—2014年城镇化过程中碳排放的驱动机制。主要结果:(1)各城市群的经济总量均有增长,能源效率逐渐提高,碳排放强度在北京、上海和重庆的是下降趋势,在天津呈上升趋势,而在广州和武汉则趋于平稳状态,各城市群能源消耗中各种能源的比重和碳排放量的变化存在着较显著的差异性;(2)天津和广州的4个碳排放影响效应整体上是逐渐增大,北京和上海是趋于平稳对称,武汉和重庆是先减小后增大。研究表明,经济和人口对碳排放具有正向作用,能源强度对碳排放具有负向作用。通过研究中国典型城市群碳排放的驱动因子,有助于城市群碳排放权交易的政策制定以及城市群发展模式规划。     

城市植物源挥发性有机化合物排放特征及其大气环境效应研究进展

在外界环境的刺激下,植物会通过释放挥发性有机化合物来维护自身生长。城市是人类活动的主要集聚地,剧烈的人为干扰导致城市环境特征呈现出复杂的变化趋势,从而使城市植物排放挥发性有机化合物的过程与自然界出现较大差异。城市中的植物源挥发性有机化合物(Biogenic Volatile Organic Compounds, BVOCs)会直接与城市中的氧化物质接触,生成二次污染物,并在高温、强光照的条件下发生光化学反应,严重破坏城市大气环境,危害居民健康。总结了城市BVOCs的常见类型、作用机制及现有研究方法,分析了不同时间、空间和人类活动背景下的城市BVOCs排放特征,并进一步梳理了当前研究的不足,提出未来重点研究方向,旨在为大气环境治理、环境空间规划、居民健康保障等方面的城市管理工作提供指导。     

A unifying conceptual model for the environmental responses of isoprene emissions from plants

Background and Aims

Isoprene is the most important volatile organic compound emitted by land plants in terms of abundance and environmental effects. Controls on isoprene emission rates include light, temperature, water supply and CO₂ concentration. A need to quantify these controls has long been recognized. There are already models that give realistic results, but they are complex, highly empirical and require separate responses to different drivers. This study sets out to find a simpler, unifying principle.

Methods

A simple model is presented based on the idea of balancing demands for reducing power (derived from photosynthetic electron transport) in primary metabolism versus the secondary pathway that leads to the synthesis of isoprene. This model''s ability to account for key features in a variety of experimental data sets is assessed.

Key results

The model simultaneously predicts the fundamental responses observed in short-term experiments, namely: (1) the decoupling between carbon assimilation and isoprene emission; (2) a continued increase in isoprene emission with photosynthetically active radiation (PAR) at high PAR, after carbon assimilation has saturated; (3) a maximum of isoprene emission at low internal CO₂ concentration (c_i) and an asymptotic decline thereafter with increasing c_i; (4) maintenance of high isoprene emissions when carbon assimilation is restricted by drought; and (5) a temperature optimum higher than that of photosynthesis, but lower than that of isoprene synthase activity.

Conclusions

A simple model was used to test the hypothesis that reducing power available to the synthesis pathway for isoprene varies according to the extent to which the needs of carbon assimilation are satisfied. Despite its simplicity the model explains much in terms of the observed response of isoprene to external drivers as well as the observed decoupling between carbon assimilation and isoprene emission. The concept has the potential to improve global-scale modelling of vegetation isoprene emission.     

Identification of Campylobacter infection in chickens from volatile faecal emissions

Volatile organic compounds from chicken faeces were investigated as biomarkers for Campylobacter infection. Campylobacter are major poultry-borne zoonotic pathogens, colonizing the avian intestinal tract. Chicken faeces are the principal source of contamination of carcasses. Fresh faeces were collected on farm sites, and Campylobacter status established microbiologically. Volatile organic compounds were pre-concentrated from the headspace above 71 separate faecal samples using solid-phase microextraction and separated and identified by gas chromatography/mass spectrometry. A Campylobacter-specific profile was identified using six of the extracted volatile organic compounds. The model developed reliably identified the presence or absence of Campylobacter in >95% of chickens. The volatile biomarker identification approach for assessing avian infection is a novel approach to enhancing biosecurity in the poultry industry and should reduce the risk of disease transmission to humans.     

人为干扰对城市森林灌草层植物多样性的影响——以厦门市为例

以厦门城市森林林下层植被为研究对象,重点研究台湾相思群落中林下灌草层植物多样性与土地利用类型、人为干扰程度之间的相关性;选用基于重要值的4种多样性指数,比较不同邻接用地类型城市森林群落多样性的差异;运用主成分分析、CCA排序以及多元回归等方法对城市森林灌草层植物多样性格局进行解释.结果表明:人为踩踏、垃圾堆积程度、人为挖掘、可到达容易程度等因子对厦门城市森林灌草层植物多样性分布格局有重要影响;厦门城市森林群落草本层β多样性沿着邻接商业用地、交通用地、工业用地、居住用地的方向逐渐增加,而灌木层β多样性沿着该环境梯度的方向却逐渐降低.     

Abatement of volatile organic sulfur compounds in odorous emissions from the bio-industry

Compounds of interest in this work are methanethiol (MeSH), dimethyl sulfide (Me₂S), dimethyl polysulfides (Me₂S_x) and carbon disulfide (CS₂) since these volatiles have been identified as predominant odorants in the emission of a wide range of activities in the bio-industry (e.g. aerobic waste water treatment plants, composting plants, rendering plants). In these processes, the occurrence of volatile organic sulfur compounds is mainly related to the presence of anaerobic microsites with consecutive fermentation of sulfur containing organic material and/or to the breakdown of the latter due to thermal heating. Due to the chemical complexity of these low-concentrated waste gas streams and the high flow rates to be handled, mainly biotechnological techniques and scrubbers can be used to control the odour emission. When using biofilters or trickling filters, inoculation with specific micro-organisms and pH-control strategies should be implemented to optimise the removal of volatile organic sulfur compounds. In scrubbers, chemical oxidation of the volatile organic sulfur compounds can be obtained by dosing hypochlorite, ozone or hydrogen peroxide to the scrubbing liquid. However, optimal operational conditions for each of these abatement techniques requires a further research in order to guarantee a long-term and efficient overall odour abatement.     

Collection of Trichogramma Westwood (Hymenoptera: Trichogrammatidae) from tropical northern Australia: a survey of egg parasitoids for potential pest insect biological control in regions of proposed agricultural expansion

Abstract  Trichogramma limit pest damage to crops by killing the developing embryo of their insect host at the egg stage. Their impact on the potentially insecticide resistant species, Helicoverpa armigera (Hübner), is considered integral to the resistance management plan for transgenic cotton production in the Ord River Irrigation Area in northern Western Australia. The dominant species of egg parasitoid in Ord River Irrigation Area cotton crops is the introduced Trichogramma pretiosum (Riley). Surveys of similar northern Australian regions earmarked for agricultural expansion revealed that T. pretiosum has been introduced, or has adventitiously dispersed, to all developing agricultural regions of northern Australia. Several previously unsequenced species were collected during surveys in more pristine habitats. Trichogramma pretiosum demonstrates an apparent ability to supersede native Trichogramma species and is perhaps favoured by agricultural expansion.     

城郊有机农场生态系统服务评估——以北京市为例

快速城市化对周边农业区域造成巨大影响。都市农业能够提供世界上20%的食品,为粮食安全做出了重要贡献。在全球环境危机的背景下,农业生态保护问题得到了越来越多的关注。有机农场在生产过程中遵循自然规律,不使用化学合成的农药、化肥和生长调节剂等物质,是实现生态农业的有效模式之一。城郊有机农场得益于临近都市的地理位置,常常同时提供参观、采摘等休闲服务,加深了游客对农业的理解和与自然的连结。目前,国内研究大多关注有机食品健康、有机农业政策和环境效益,但往往忽视其提供的经济和文化价值。基于生态系统服务与人类福祉关系的概念框架,以北京市为例,从供给、调节、文化三个方面全面评估城郊有机农场的生态系统服务。结果显示,截至2019年北京市城郊共有271家有机农场,种植面积1.09万hm²,占北京市耕地面积的5.1%。供给服务价值为16.12亿元。调节服务方面,提供了2140万元的土壤碳固存价值,并且比相同面积的常规农场减少了16.4万GJ能量、2639tCO₂、202tSO₂和29tPO₄^3-的排放。文化服务方面,提供了1.189亿元的采摘服务,并促成了120余次农夫市集和50余次讲座、沙龙的宣传教育活动,积累了社会资本。本研究尝试通过直观的数据全面反映城郊有机农场对收益者的多种惠益,凸显了在有限的供给服务之外,城郊有机农场在休闲游憩和教育宣传等文化服务的贡献,为深入理解城郊有机农场生态系统服务提供基础,有助于进一步提高农业管理的精细程度和城市的可持续性。     

Structure of ant assemblages on street trees in urban Busan,Korea

Street trees planted in urban areas are one of the smallest urban green habitats; however, their role as a valuable refuge for local biota is poorly understood. The aim of this study was to investigate urban street trees as habitat for ants. We found ants on 195 (92%) of 211 street trees studied. Seventeen ant species were collected from five tree species. The two most common ant species were Tetramorium tsushimae (on 112 trees) and Lasius japonicus (on 93 trees). The number of ant species found per tree ranged from 0 to 5, with a mean of 1.55 ± 0.92. The species composition differed significantly among tree species. Nine ant species (Camponotus vitiosus, Lasius alienus, L. japonicus, Nylanderia flavipes, Crematogaster matsumurai, Crematogaster vagula, Monomorium intrudens, T. tsushimae, and Brachyponera chinensis) nested on the trees, mostly in the root zone. Nests were found on 150 trees but were relatively rare on trees with diameter at breast height of less than 40 cm.     

干旱区绿洲城市树木健康评估及影响因素——以乌鲁木齐市为例

树木作为城市绿色基础设施重要组分,其健康直接影响城市生态系统服务及人居环境质量。城市化进程加快导致生态土地缺失,同时缺乏合理养护加之极端自然条件干扰对树木健康造成严重威胁。为揭示城市树木健康风险及影响因素,对乌鲁木齐市核心城区117个样地绿化树木进行健康评估,从4个维度12个指标构建树木健康分级体系,基于样地调查结果,分析树木组成、结构、关联性、健康状况及影响因素,揭示乌鲁木齐市不同功能区树木健康差异。旨在为研究区树木健康保护、城市绿地可持续经营及城市生态文明建设提供理论依据和数据支撑。结果表明：（1）乌鲁木齐市城市园林树木乔灌比为8.3 ： 1,树木多样性与种间关联程度较低。榆树占比高达43.87%,其中白榆占比22.62%,是主要优势树种;（2）不同树种健康程度呈现差异性,榆树类健康状况呈现圆冠榆 > 大叶榆 > 白榆 > 垂枝榆特征;（3）城市不同功能区树木健康也呈现异质性;以公园和居住小区树木健康分值较高,而行道树和学校庭院树木健康分值相对较低,且冗余分析进一步揭示地面铺装、林木配置结构、生长空间和胸径对树木健康影响程度最为显著。未来优化城市树木生境条件、提升物种丰富度、加强古树名木保育和提高园林绿化管理水平是维护和提升绿洲城市树木健康的重要举措。