春季城区道路不同绿地配置模式对大气颗粒物的削减作用

研究城市道路不同绿地类型对大气颗粒物的吸附削减作用,是提高城市绿地大气污染治理功能绿地配置模式优化的重要基础。以位于北京市海淀区的3条典型主干道道路为对象,选取乔木、灌木、草本、乔-灌、乔-草、乔-灌-草6种典型绿地配置模式,在大气颗粒物污染严重以及城市植被发芽、开花、展叶完成的春季(3月中旬至4月上旬),采用Dustmate便携式颗粒物采样器和NK4500手持自动气象仪分1.5m和3m两个高度同步测定距污染源不同位置的大气颗粒物浓度与小气候因子,分析不同绿地配置模式对颗粒物削减能力的差异及其主要影响因素。研究结果表明:复合配置模式比单一配置模式下空气颗粒物浓度稳定程度高,其主要受风速与空气相对湿度的影响;大气颗粒物粒径越大绿地对其削减作用越强;地表覆盖程度是影响不同绿地配置模式对大气颗粒物垂直削减的关键因素,地表覆盖越好垂直削减效果越好,且垂直削减率与温度成正相关关系;草本、灌木对大气颗粒物的垂直削减作用比其他4种配置模式更好;由于受植被郁闭度、疏透度以及配置种类的综合影响,乔-草、灌木绿地配置对大气颗粒物的水平削减作用比其他4种模式更好。     

基于城市微气候模拟软件的城市道路绿化带对PM2.5消减作用的研究

随着经济的快速发展及机动车保有量的持续增长，车辆造成的道路污染问题日益严重。广州作为中国重要的经济发展城市，交通源排放问题高度集中，机动车排放是城市PM2.5的主要来源之一，开展减缓城市道路污染危害的研究具有重要意义。本研究为调查绿化带对广州城市道路PM2.5的影响，运用实测与城市微气候模拟软件（ENVI-met）模拟结合的研究方法，实测并分析城市道路空间PM2.5的浓度分布及其影响因素，使用实测数据对模拟软件进行验证分析，模拟研究理想道路模型下不同高宽比、风向等因素及绿化带植配类型对PM2.5的消减作用。研究表明：（1）城市道路空间PM2.5浓度分布受污染源、街道高宽比、风速风向、绿化带等综合影响，自然消减情况下，其主要受风速风向和高宽比双因素影响；（2）通常街道高宽比越大，越有利于道路空间PM2.5的扩散；（3）城市道路空间PM2.5自然沉降最小距离为12 m，0-12 m范围内应保持无障碍物的开敞环境，PM2.5消减的关键范围是12-24 m，此范围内可以利用生态手段沉降颗粒物；（4） PM2.5消减率受绿化带和风向的双控制，应根据主导风向选择绿化带植配方式。在主导风平行面和垂直迎风面绿化带对PM2.5有正消减效应，建议植配类型为"乔-乔+灌+草"；在主导风垂直背风面绿化带对PM2.5呈负消减效应，植配类型为"乔-灌"绿化带消减率接近于自然消减率，而植配类型为"乔-灌+草"和"乔-乔+灌+草"的绿化带加重了颗粒物在该区域的积聚。     

近20年来京津冀地区土壤风蚀扬尘颗粒物排放变化

京津冀地区是我国大气污染严重区域,土壤扬尘颗粒物排放变化研究对于改善京津冀地区空气质量具有重要意义。收集2000-2019年京津冀地区气候、土壤、植被覆盖数据,分析近20年来京津冀地区土壤扬尘颗粒物排放变化,揭示其变化的影响因素。结果显示2000-2019年京津冀地区土壤扬尘源总悬浮颗粒物（TSP）排放系数均值为1.79 t km^-2 a^-1,其中PM10占8.99%,PM2.5占0.25%。近20年土壤扬尘源TSP排放系数具有下降趋势,PM10和PM2.5排放系数变化过程与TSP一致。上述变化主要受气候因子变化影响,其次受植被覆盖度影响。分析发现近20年来京津冀地区土壤扬尘源TSP排放系数变化主要受年降水量影响。沧州市、天津市和石家庄市土壤扬尘源TSP、PM10和PM2.5排放系数均值较高,张家口市、保定市和沧州市土壤扬尘源TSP排放量占京津冀地区总量的19.18%、12.98%和11.63%。耕地土壤扬尘排放量最大占京津冀地区总量的59.83%,是抑制土壤扬尘源颗粒物排放的重点关注对象,其次为草地占15.66%。2019年邢台市土壤扬尘源PM10排放占观测值比例最高为12.66%,石家庄市和天津市占比也较高分别为11.09%和10.30%,沧州市和邯郸市占比分别为8.63%和8.02%。上述地区环境管理部门均应关注土壤扬尘源颗粒物排放对空气质量的影响。     

The Level of Particulate Matter on Foliage Depends on the Distance from the Source of Emission

One of the most dangerous inhaled pollutants is particulate matter (PM). PM in inhaled air have a negative impact on human wellbeing and health, and may even cause deaths. Where pollutants have been emitted into the outdoor atmosphere, the only possible method for cleaning the air is through phytoremediation, a form of environmental biotechnology, where plants act as biological filters for pollutants. This study compared PM levels on the leaves of Tilia cordata Mill. trees growing in locations at increasing distances from the source of the PM emission. Significant differences between individual trees growing at a distance of between 3 m and 500 m from the road edge were found in: (i) the mass of PM that accumulated on leaves (total, surface, in-wax and the three determined size fractions) and (ii) the amount of waxes deposited on leaves.     

钙素和水分亏缺对黄瓜叶片细胞质膜透性的影响

用控制溶液的钙量[加或不加Ca(NO_3)_2]和渗透势(加聚乙二醇6000,202 g/L)的方法,研究了钙素和水分亏缺对黄瓜叶片细胞质膜透性的影响。结果表明:在渗透胁迫下,正常供钙的黄瓜叶片相对含水量(RWC)和膜透性变化较小、MDA增加不显著、SOD活性无明显改变;缺钙植株叶片的RWC随渗透胁迫处理线性下降,膜透性显著增大、MDA含量迅速提高、SOD活性也升高。在正常水分供应下,与供钙植株相比,缺钙植株SOD活性和MDA含量均较高,但RWC和膜透性无差异。在水分胁迫下,缺钙植株MDA和质膜透性与ΔRWC以及MDA与质膜透性之间均呈正相关。这些结果表明在水分胁迫下,缺钙处理叶片保水能力降低,使受害加重;同时,细胞质膜的稳定性降低。膜透性改变可能与在水分胁迫下体内的膜脂过氧化反应密切相关,即缺钙加速了膜脂过氧化反应,从而损害了质膜结构。     

陕北长城沿线植被恢复与生态系统防风固沙服务模拟分析

为探究风沙边缘地区植被恢复与生态系统防风固沙服务能力之间的作用机制以及如何保证防风固沙服务的可持续发展,选择毛乌素沙漠边缘地区--陕北长城沿线为研究区。利用Theil-Sen斜率估算、M-K显著性检验、修正风蚀方程（Revised Wind Erosion Equation,RWEQ）和情景分析法,评估分析2000-2018年该地风沙治理工程效果和生态系统防风固沙服务的时空变化,并着重分析在风蚀因子改变的条件下,植被恢复对土壤风蚀和生态系统防风固沙服务能力的影响。结果表明：（1）在2000-2018年风沙治理工程中陕北长城沿线地区植被恢复状况显著改善,表明多年来在风蚀治理工作中取得显著的效果。（2）在实际情景中,随着植被不断的恢复,风蚀发生的危险程度总体在减小,而风蚀因子是导致实际风蚀量显著改变的主要原因。从生态系统防风固沙服务角度出发,在不同年份防风固沙总量变化显著,2005年和2010年防风固沙量达到最小、最大值,分别为4569.18万t和64164.44万t,差异明显,致使2005和2010年防风固沙服务能力也达到历史最低和最高值。（3）通过最小风蚀因子情景模拟间接表明：植被恢复能够遏制风蚀现象的发生。但在最大风蚀因子情景下,风蚀现象依旧明显,而植被所发挥的生态系统防风固沙服务能力越显著。（4）综合上述3种情景,每年潜在风蚀量 > 防风固沙量 > 实际风蚀量,说明在最大危害程度内生态系统防风固沙服务具有明显的效果。通过研究不仅证实植被是实现防风固沙服务功能可持续发展的必要条件,同时恢复植被对风沙区域进一步发展状况与趋势有着至关重要的作用。     

植物源VOCs及其对陆地生态系统碳循环的贡献

综述了近20a来国内外关于植物源VOCs的研究进展。分析了植物源VOCs主要组成成分、生理-生态基础,以及影响植物VOCs释放速率的主要因素。重点探讨了植物源VOCs对陆地生态系统碳循环的潜在重要性,提出一些值得关注的问题。     

长白山寒温带风灾区植被受损与灾后变化程度及其影响因素

1986年台风袭击了长白山,在西、南坡的寒温带针叶林和岳桦林带形成了大量林窗.为了探究在强风干扰下寒温带森林植被受损和变化特征,揭示植被受损与灾后变化规律及其影响因子,2017年在长白山海拔1600～1800 m设立研究区.利用遥感资料,对研究区依据植被破坏程度和灾后变化程度进行植被差异分区,并布设了40个样方进行植被调查.结果表明: 按森林结构的受损程度可将长白山寒温带风灾区分为3个等级,轻度破坏、中度破坏和重度破坏,其中,中度破坏区的面积最大,其次是轻度破坏区、重度破坏区.乔木受损差异显著,轻度破坏区、中度破坏区和重度破坏区乔木优势种的数量分别减少20%、50%和85%,岳桦的抗风性大于鱼鳞云杉,大径级岳桦的抗风性大于小径级的岳桦.植被受损程度与坡度的相关性最强,随着坡度的增加,受风灾破坏程度减小.1987—2017年间,长白山寒温带风灾区的植被发生明显变化,根据变化的程度可将研究区分为3个等级:变化快、变化中等和变化慢,其中,变化中等的区域面积最大,其次是变化慢、变化快的区域;植被变化程度与海拔的相关性最强,随着海拔的增加,植被变化变慢.乔木的恢复较慢,鱼鳞云杉略好于岳桦;植被变化主要表现在灌木层和草本层,变化快的区域灌木层发育好于草本层;变化中等的区域草本层发育好于灌木层;变化慢的区域灌木层发育差异大,但草本层总体上表现为低矮稠密.     

An analysis of the pollution problem in Slavonski Brod (eastern Croatia)

H2S, PM2.5, O3, NO2, SO2 and meteorological parameters such as temperature, relative humidity, precipitation, wind speed and wind direction were measured simultaneously in an eastern Croatian town called Slavonski Brod during the season winter/spring 2010. Emissions from the nearby cross-border (Bosnia and Herzegovina) oil refinery were identified as sources of temporary elevated concentrations of H2S. The maximum daily averages of PM2.5 concentrations during the winter period were as high as 240 microg m(-3) which is a value 10 times greater than the threshold prescribed by the World Health Organization. It is considered that the heating season, dense traffic, intense industrial activities and temperature inversion during stable weather conditions are prevailing contributors to higher winter concentrations of PM2.5. The results of the principal component analysis technique (PCA) have shown that lower air temperature, lower wind speed and higher relative humidity play a significant role in the winter pollution episodes. From a public health point of view, implementation of measures aimed at reducing the levels of H2S and PM2.5 should be considered.     

Alterations in anaerobic ammonium oxidation of paddy soil following organic carbon treatment estimated using 13C-DNA stable isotope probing

In this study, soil samples from the typical rice-wheat cropping system in Jiangsu Province, China, subjected to different fertilizer application treatments―no carbon (CK), urea (UR), straw (SR), pig manure (PM), starch (ST), and glucose (GL)―were used to determine potential anaerobic ammonium oxidation (anammox) rate and its association with bacterial abundance, diversity, and activity by using DNA stable isotope probing combined with ¹⁵N isotope tracing and molecular techniques. The effects of different organic carbon sources on anammox were significant, in the following order: GL > ST, SR > UR > PM; anammox activity differed significantly across treatments; however, the ¹³C active anammox bacteria were only closely related to Ca. Brocadia. The anammox hydrazine synthase β subunit functional gene sequences were highly associated with the Candidatus genus Brocadia in PM and CK treatments. The different organic carbon sources had different inhibitory effects with anammox rate, which dropped from 3.19 to 1.04 nmol dinitrogen gas g⁻¹ dry soil h⁻¹ among treatments. About 4.2–22.3% of dinitrogen gas emissions were attributed to anammox and indicated that a specific population of anammox bacteria was present and varied with the addition of exogenous organic compounds in paddy soils, although a small part of dinitrogen gas was emitted from the soil via anammox.

     

A continuous loading apparatus for measuring three-dimensional stiffness of ankle-foot orthoses

This paper describes a novel device to evaluate the mechanical properties of ankle foot orthoses (AFOs). The apparatus permits the application to AFOs of continuous three-dimensional (3D) movements between specified and settable endpoints. Using an x-y robot with a rotary stage and a six-component load cell, characteristic displacement versus reaction force curves can be generated and consequently the ankle moments can be determined as a function of dorsi/plantar flexion, inv/eversion and int/external rotation. Representative curves for two polypropylene lateral leaf AFOs, different in shape but produced for the same leg by a skilled orthotist, are presented to illustrate the capabilities of the novel testing system. The metrological investigation showed that the apparatus creates a highly repeatable data set (uncertainty < or = 1% FSO).     

Do carnivorous plants use volatiles for attracting prey insects?

1.  Scientists have been fascinated by carnivorous plants for centuries and they have thoroughly investigated how these plants can benefit from insect capture for example through increased growth, earlier flowering, and increased seed production. How prey is actually lured into the traps, however, is less well understood. Trapping prey may be achieved in a random way, for example by camouflaging the traps (hiding them in the surrounding vegetation), so that prey is trapped by accidental landing on the trap leaves or wind drift, or in the other extreme, trapping may involve mimicry of other attractive resources such as fruits or flowers by using specific visual or olfactory signals to attract a specific prey assemblage.
2.  We investigated for the first time volatiles of the trapping leaves of carnivorous plant species by dynamic headspace methods. We present data on the venus flytrap Dionaea muscipula , the sundew Drosera binata , and the North American pitcher plants Sarracenia flava , Sarracenia leucophylla , Sarracenia minor , and Sarracenia purpurea . A large number of compounds and relatively high emission rates were found in three of the North American pitcher plants ( S. flava , S. leucophylla , and S. minor ) with compounds typically found in flowers or fruits. This suggests together with other features (e.g. colour, nectar production) that these traps are possibly flower or fruit mimics. The leaves of S. purpurea , Dionaea muscipula , and Drosera binata emitted much weaker scents with lower numbers of components, consisting mainly of volatiles typically emitted from green leaves.
3.  We discuss whether or not the use of volatiles for attracting prey animals is linked with specific trapping mechanisms and whether carnivorous plants can be grouped into specialized 'olfactory syndromes'.     

Prioritizing forest fuels treatments based on the probability of high‐severity fire restores adaptive capacity in Sierran forests

In frequent fire forests of the western United States, a legacy of fire suppression coupled with increases in fire weather severity have altered fire regimes and vegetation dynamics. When coupled with projected climate change, these conditions have the potential to lead to vegetation type change and altered carbon (C) dynamics. In the Sierra Nevada, fuels reduction approaches that include mechanical thinning followed by regular prescribed fire are one approach to restore the ability of the ecosystem to tolerate episodic fire and still sequester C. Yet, the spatial extent of the area requiring treatment makes widespread treatment implementation unlikely. We sought to determine if a priori knowledge of where uncharacteristic wildfire is most probable could be used to optimize the placement of fuels treatments in a Sierra Nevada watershed. We developed two treatment placement strategies: the naive strategy, based on treating all operationally available area and the optimized strategy, which only treated areas where crown‐killing fires were most probable. We ran forecast simulations using projected climate data through 2,100 to determine how the treatments differed in terms of C sequestration, fire severity, and C emissions relative to a no‐management scenario. We found that in both the short (20 years) and long (100 years) term, both management scenarios increased C stability, reduced burn severity, and consequently emitted less C as a result of wildfires than no‐management. Across all metrics, both scenarios performed the same, but the optimized treatment required significantly less C removal (naive=0.42 Tg C, optimized=0.25 Tg C) to achieve the same treatment efficacy. Given the extent of western forests in need of fire restoration, efficiently allocating treatments is a critical task if we are going to restore adaptive capacity in frequent‐fire forests.     

森林植被与大气颗粒物的关系

近年来,大气颗粒物成为我国城市大气的主要污染物,其中细颗粒物（PM_2.5）粒径小、沉降困难,对环境的危害已成为亟待解决的问题。森林植被可显著消减空气颗粒物,有效改善空气环境质量。本文概述了植被对颗粒物的移除过程和方法,探讨了大气颗粒物与森林植被的相互关系。从单叶、单木及群落3个尺度,结合气象因素讨论了植被对移除大气颗粒物的影响,分析了颗粒物的后续再悬浮过程及对植被的危害。最后,从植被吸附颗粒物的能力测定和评价、本土高吸附PM_2.5能力植被的筛选及综合研究不同植被配置结构的吸附效应等方面提出了植被吸附颗粒污染物,尤其是细颗粒物的研究重点与趋势。     

一种测定植物挥发物对棉铃虫引诱作用的无选择性风洞嗅觉仪(英文)

发展了一套测定棉铃虫Helicoverpaarmigera (H櫣ｂｎｅｒ)对植物挥发物的行为反应的生测系统。这套系统由嗅觉仪、风洞和风洞室组成。用这套系统测定了棉铃虫对萎蔫后的枫杨Pterocaryastenoptera叶、加拿大杨Populuscanadensis叶、香椿Toonasisnensis叶、新鲜的芹菜与胡萝卜花挥发物以及苯乙醛的行为反应。结果显示 ,萎蔫的枫杨叶、加拿大杨叶、香椿叶的挥发物均对棉铃虫处女雌蛾表现出显著的引诱作用 ,而对已交配过的雌蛾和雄蛾无明显的引诱作用 ;新鲜的芹菜与胡萝卜花挥发物对棉铃虫两性性成虫均不表现出显著的引诱作用 ;苯乙醛对棉铃虫处女雌、雄蛾有较强的引诱作用。讨论了杨树枝把引诱棉铃虫的原因。     

基于规划目标的京津风沙源治理区生态保护与修复效应

为改善和优化京津及周边地区生态环境状况,减轻风沙危害,2003年启动实施了京津风沙源治理工程。基于工程规划目标评估了京津风沙源治理区生态保护与修复效应,结果表明:(1)草地和林地作为京津风沙源治理区绿色生态屏障的主要组成,分别占治理区面积的57.3%和9.7%,而风沙策源地的耕地和沙地分别占17.2%和6.4%。(2)2003—2017年,京津风沙源治理区草地、耕地、沙地面积减少,而林地和其他类型面积增加。治理区植被覆盖度平均提高了2.3%,其中林地提高了4.3%,草地提高了2.4%。(3)沙尘天气发生的春季,治理区土壤风蚀量减少了54%。在防风固沙服务总量的贡献中,草地和沙地贡献了71%。因此,草地和沙地生态系统的植被恢复,对治理区生态系统防风固沙服务的提高发挥了最为重要的作用。(4)除治理区植被有所恢复外,由于气候整体变暖,近15年风场强度有所减弱,特别是沙尘天气易发生的春季风场强度减弱近45%,也是影响京津风沙源治理区风蚀量下降的一个重要原因。     

Spatial risk modeling of cattle depredation by black vultures in the midwestern United States

Negative economic impacts resulting from wildlife disrupting livestock operations through depredation of stock are a cause of human-wildlife conflict. Management of such conflict requires identifying environmental and non-environmental factors specific to a wildlife species' biology and ecology that influence the potential for livestock depredation to occur. Identification of such factors can improve understanding of the conditions placing livestock at risk. Black vultures (Coragyps atratus) have expanded their historical range northward into the midwestern United States. Concomitantly, an increase in concern among agricultural producers regarding potential black vulture attacks on livestock has occurred. We estimated area with greater or lesser potential for depredation of domestic cattle by black vultures across a 6-state region in the midwestern United States using an ensemble of small models (ESM). Specifically, we identified landscape-scale spatial factors, at a zip code resolution, associated with reported black vulture depredation on cattle in midwestern landscapes to predict future potential livestock depredation. We hypothesized that livestock depredation would be greatest in areas with intensive beef cattle production close to preferred black vulture habitat (e.g., areas with fewer old fields and early successional vegetation paired with more direct edge between older forest and agricultural lands). We predicted that the density of cattle within the county, habitat structure, and proximity to anthropogenic landscape features would be the strongest predictors of black vulture livestock-depredation risk. Our ESM estimated the relative risk of black vulture-cattle depredation to be between 0.154–0.631 across our entire study area. Consistent with our hypothesis, areas of greatest predicted risk of depredation correspond with locations that are favorable to vulture life-history requirements and increased potential to encounter livestock. Our results allow wildlife managers the ability to predict where black vulture depredation of cattle is more likely to occur in the future. It is in these areas where extension and outreach efforts aimed at mitigating this conflict should be focused. Researchers and wildlife managers interested in developing or employing tools aimed at mitigating livestock-vulture conflicts can also leverage our results to select areas where depredation is most likely to occur.     

Cameraria ohridella: 10 years of sex pheromone and kairomone research

This review traces the identification and use of sex pheromone of the horse chestnut leafminer Cameraria ohridella Deschka et Dimi? (Lepidoptera, Gracillariidae, Lithocolletinae) to monitor population density and discuss its potential for direct control. Host volatiles endogenously emitted from Aesculus hippocastanum L. leaves are described in terms of their ability to control conspecific females.     

The interrelationship between plant species distribution and properties of soils undergoing podzolization in a coastal area of S.W. Australia

A study of soil and vegetation characteristics within a small area of coastal heath near The Gap, Albany, Western Australia, showed that significant differences exist in plant species composition between podzol and non-podzol (calcareous) soil environments. Leaf extracts of common plant species from podzol, non-podzol and transitional soil sites were tested for their ability to complex with iron. Only those species on the podzol and transitional soils proved to have this ability. Soil column experiments tested the rates of iron mobilization and results indicate that the podzol vegetation elutant solution, which was found to contain the iron-complexing agent gallic acid, was superior to the non-podzol vegetation elutant solution in the rate at which it mobilized iron. It is suggested that initiation of podzolization is due to the presence of gallic acid in the leaves of certain of the species in the coastal heath association, and that the pattern of podzol distribution can be linked to both plant succession and inherent differences in soil parent material.     

A NO‐CHOICE WIND TUNNEL OLFACTOMETER SYSTEM FOR EVALUATING THE ATTRACTIVENESS OF PLANT VOLATILES TO ADULT HELICOVERPA ARMIGERA (HÜBNER) (LEPIDOPTERA:NOCTUIDAE) *

Abstract A bioassay system to evaluate adult cotton bollworm (CBW), Helicoverpa armigera, behavioral responses to plant volatiles was described. The system was comprised of a no‐choice olfactometer, a wind tunnel, and a wind tunnel room. The olfactometer was designed to provide for the testing and evaluation of volatiles from a variety of natural and synthetic sources. The behavioral responses in this system demonstrated that the volatiles of wilted leaves of Pterocarya stenoptera, Toona sinensis and Populus canadensis, the main materials of which poplar bundles were made, only could attract virgin females but not mated females and males. The volatiles emitted from fresh carrot and celery flowers did not exhibit significant attractiveness to both sexes of CBW. 0.1% phenylacetaldehyde showed significant attraction for virgin females and males. The biological significance of attraction of volatiles from these plants for CBW was discussed.