共查询到18条相似文献，搜索用时 311 毫秒
1.
为研究城市道路不同植物配置模式对大气中PM2.5和PM10浓度的削减作用,以郑州市建设路为研究对象,选取4种乔-灌型植物配置,采用便携式颗粒物检测仪器(CW-HAT200S)及气象仪(Kestrel 5000)测定其PM2.5、PM10浓度和气象因子,分析乔-灌型植物群落对PM2.5和PM10浓度在垂直空间和水平空间的削减作用。结果表明,道路环境下PM2.5和PM10浓度在垂直方向和水平方向的日动态变化规律表现较为一致,均呈“U”型,早晚高,中午低;颗粒物浓度与温度、风速呈显著负相关,与湿度呈显著正相关;削减率与温度、风速和湿度的相关关系不明显。乔木枝下高较低、有多层高度的配置形式对颗粒物的削减更有效果,群落配置“美人梅+红叶石楠+黄杨”在垂直方向上削减效果最好,群落配置“悬铃木+海桐+构骨”在水平方向上削减效果最好。 相似文献
2.
为研究湖北省咸宁市的大气细颗粒物PM2.5的污染特征及来源情况,于2022年选取咸宁市内2个环境受体点位作为采样点,对不同季节的PM2.5进行采集,对细颗粒物PM2.5的组成成分及来源进行统计分析：基于采样情况构建本地PM2.5的特征源谱,利用化学质量平衡模型CMB对PM2.5的来源进行了解析。结果表明：咸宁市大气细颗粒物PM2.5的季节浓度均值呈现为冬季>秋季>春季>夏季的变化趋势,PM2.5的主要组成包括水溶性无机盐与含碳组分,一次来源解析结果显示PM2.5的主要贡献源是二次气溶胶,贡献率在47.15%;二次来源解析结果显示贡献最大的是工业源和机动车,贡献率分别为34.86%和28.94%。根据上述分析结果,咸宁市在大气细颗粒物PM2.5的治理方面,应采用综合治理措施,要关注对工业、机动车排放的控制,以及对能源结构的调整,以获取到更好的治理效果。 相似文献
3.
使用2015~2017年我国29个城市的空气污染物PM2.5、PM10、O3浓度和气象要素(包括气压、气温、相对湿度、降水量、风速、日照时数)日数据,对每个城市空气质量变化特征与气象要素的月平均值进行了线性相关和多元回归模型分析,然后Meta分析合并相关系数和回归系数。结果表明:PM2.5浓度与所有气象变量(除风速)呈相关、PM10浓度与所有气象变量呈相关,而O3也与所有气象变量(除相对湿度)呈相关,但O3与气象变量的相关方向和PM2.5、PM10相反。通过对污染物浓度和气象变量的多元回归分析,21个城市的空气污染都得到较好程度的解释(R2>0.5)。同时,对影响PM2.5、PM10和O3的主要气象因素的效应进行了合并。 相似文献
4.
以广州市3个公园不同配置模式的植物群落为样地,测定分析其抑菌功能。结果表明:植物群落具有良好的抑菌作用;抑菌效果强度大小依次是乔灌草结构乔草结构草坪结构灌草结构;植物群落的抑菌效果在不同时刻的表现也不尽相同,乔灌草、灌草和草坪的抑菌效果均在16:00达到最好,灌草和草坪结构在8:00最差。 相似文献
5.
城市园林绿地消减大气PM2.5浓度研究进展 总被引：1，自引：0，他引：1
园林绿地能有效消减城市空气中的PM2.5浓度，缓解大气污染状况。文中结合现有研究，综合阐述园林绿地消减PM2.5浓度的作用机理，探讨园林绿地消减PM2.5浓度的日变化和年变化规律及其原因，分析园林绿地中植物种类、绿地结构、绿地面积和宽度对大气PM2.5浓度的消减作用，总结温度、相对湿度、风速、车流量等环境因子以及不同污染条件对PM2.5浓度分布和扩散的影响，提出了园林绿地消减PM2.5浓度的研究趋势，指出应进一步探讨PM2.5对植物生长的影响、城市园林绿地消减PM2.5浓度的尺度效应、城市绿色空间滞尘功能评估以及PM2.5的消减量与健康效益的关联性等。 相似文献
6.
2018-2019年在荥阳生态站每月监测3次空气颗粒物PM2.5、PM10(PM)和负氧离子的浓度,分析了荥阳生态站两种PM质量浓度日变化、月变化、季节变化特征;用监测日的气象因子日均值、空气负离子浓度日均值与两种PM质量浓度做相关分析,以期了解PM质量浓度时间变化特征及相关影响因子。结果表明：两种PM浓度的日变化在8:00～18:00浓度变化呈U型。8:00～9:00浓度较高8:00～17:00浓度呈下降趋势,17:00以后质量浓度上升。月变化中11月至次年4月月平均质量浓度高;5～10月份平均质量浓度为较低。两种PM季节平均质量浓度高低顺序为：夏季<秋季<春季<冬季。春季和冬季两种PM污染尤为严重。PM2.5质量浓度与气温呈极显著负相关;与日照时数、气温呈显著负相关,与气压呈显著正相关;与负离子浓度呈极显著负相关;与PM10呈极显著正相关。PM10质量浓度与气温、气温日较差呈显著负相关。 相似文献
7.
PM10和PM2.5是大气雾霾重要来源。为探究绿化针叶树种滞尘能力,本研究以冀西北张家口市油松、侧柏、白皮松、青杄4种针叶树种为研究对象,分析不同树种、月份之间叶片滞纳PM10和PM2.5差异。结果显示：(1)针叶树种PM10滞纳量在1.89～2.64μg·cm-2之间,PM2.5滞纳量在0.63～0.80μg·cm-2之间,其中,油松PM10和PM2.5滞纳量均最大,青杄均最小,不同树种之间均无明显差异。(2)10月PM2.5和PM10滞纳量均最大(1.40μg·cm-2、4.43μg·cm-2),8月均最小(0.41μg·cm-2、1.12μg·cm-2),10月份平均滞纳量显著均大于其他月份。(3)每公顷每年PM10 相似文献
8.
利用河北省2017~2018年逐日PM2.5浓度地面观测数据和CUACE空气质量模式的PM2.5气象条件评估指数(EMI,evaluation on meteorological condition index of PM2.5 pollution),定量评估了2018年相比2017年河北省冬季气象条件对PM2.5浓度的贡献,并分析了石家庄市气象条件和PM2.5浓度的同期月变化。结果表明:与2017年相比,2018年冬季河北省气象条件不利于PM2.5浓度的下降,其中,北部、西北部地区气象条件极为不利,使PM2.5浓度同比上升28%~45%,不同城市的气象条件变化存在显著差异;2018年石家庄市PM2.5年均浓度同比下降12.7%,其中气象条件使PM2.5浓度同比下降3.1%,说明石家庄市大气污染防治减排措施对PM2.5浓度下降贡献显著。可见,EMI指数可定量诊断和评估污染期间气象条件对PM2.5浓度的影响。 相似文献
9.
为揭示江西省新余市森林游憩区空气负离子与PM2.5时空分布特征、交互效应及其影响因素,对其森林环境中空气负离子和PM2.5浓度时空分布特征及其与气象因子关系进行测定分析。结果显示：(1)新余市森林游憩区与城市绿地空气负离子年变化趋势总体保持一致,全年中各月份森林空气负离子浓度均显著高于城市绿地;1月、3月和4月城市绿地PM2.5浓度显著高于森林,其他月份差异不明显;夏季6—8月空气负离子和PM2.5浓度分别达到其全年最高值和最低值。(2)森林环境空气负离子浓度随海拔升高呈逐渐上升的趋势,PM2.5含量呈先上升再下降的趋势;随距地面垂直高度的增加,林分中空气负离子浓度先下降再上升后保持不变,PM2.5含量逐渐降低,距地面高10 m处林冠中层具有较高的空气负离子和较低的PM2.5含量。(3)不同季节森林空气负离子与PM2.5浓度均呈显著负相关,与空气气压、温度、相对湿度、风速和风向相关性各不相同。结果表明：新余市森林... 相似文献
10.
森林火灾是一种突发性强、随机性高、扑救极为困难的自然灾害，在森林燃烧过程中可释放出高浓度PM2.5颗粒物。PM2.5是除直接烧伤和窒息外，对森林火灾扑救人员生命安全造成巨大威胁的重要污染物之一，也会给林区居民身心健康带来严重危害。文中结合国内外以森林火灾、计划烧除、室内模拟燃烧等为实验手段的森林燃烧研究，总结森林燃烧释放PM2.5的采样方法、成分分析、扩散研究、控制方法等研究进展，分析影响森林燃烧释放PM2.5的气象因素、可燃物特征、林火行为等因素，以期为提高森林火灾扑救效率、降低火灾扑救过程中的伤亡事故以及后续相关研究提供参考。 相似文献
11.
SO2和NO2为我国大气污染主要污染物,城市森林对SO2和NO2具有一定的抵抗能力和吸收净化能力,利用城市森林对大气污染进行修复具有良好的应用前景.文章概述了我国SO2和NO2气体污染的状况,总结了污染物进入植物体的过程及其损伤机理,并从植物抗性和吸附净化能力两方面总结了城市景观树种与SO2和NO2气体污染的关系研究,并基于研究结论提出今后研究可能发展方向,如SO2、NO2与悬浮颗粒物等复合污染对城市树种生长的影响、树种抗性和吸附能力综合研究等. 相似文献
12.
采用盆栽控制试验,研究了不同浓度(0、60、120和180 mmol·L-1)Na2SO4胁迫对沙枣幼苗生长和光合特性的影响。结果表明:(1)盐胁迫对沙枣幼苗生长具有显著的抑制效应。不同浓度Na2SO4胁迫沙枣的株高、侧枝数、总叶面积、单株叶片数、比叶面积以及各组织(除根)生物量均显著低于对照,且均随盐胁迫浓度的升高呈下降趋势,而根冠比值则由对照的0.153 1显著增加到180 mmol·L-1Na2SO4胁迫幼苗的0.348 7。(2)盐胁迫显著降低了沙枣幼苗的光合能力。随着Na2SO4胁迫的加剧,净光合速率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci)和蒸腾速率(Tr)均呈下降的趋势,而气孔限制值(Ls)和水分利用效率(WUE)则依次增加,且Pn下降主要受气孔限制;180 mmol·L-1Na2SO4胁迫沙枣幼苗的Pn、Gs、Ci和Tr分别为对照的71.57%、30.85%、67.15%和51.65%,而Ls和WUE则分别为对照的1.91、1.38倍。(3)盐胁迫强度与幼苗株高、总叶面积、单株叶片数、比叶面积、茎生物量、叶生物量、总生物量等生长指标以及Pn、Gs、Ci、Tr等光合参数呈极显著负相关,叶片的光合参数与总叶面积、单株叶片数呈显著或极显著正相关,而叶片的生长指标、光合参数与幼苗的株高生长和生物量累积也呈显著或极显著正相关。 相似文献
13.
[目的]探讨O_3浓度升高对两种亚热带树木幼苗的影响,并分析其敏感性差异及原因。[方法]本试验以1年生桢楠和闽楠幼苗为材料,采用开顶式气室(OTCs),研究未过滤大气、100 nmol·mol-1(E1)、150 nmol·mol-1(E2)O_3处理对光合作用、抗氧化能力和生物量的影响。[结果]研究表明:(1) O_3熏蒸主要通过非气孔限制因素降低了两树种的净光合速率(Pn)。其中对于桢楠,E2对Pn的不利影响大于E1。而对于闽楠,8月份E2的Pn大于E1,而9月份和10月份小于E1。(2) O_3熏蒸提高了两树种的抗氧化能力,表现为总酚含量和总抗氧化能力随着O_3浓度的升高逐渐升高,而E2的还原型抗坏血酸含量低于E1。(3) O_3熏蒸降低了两树种根、茎、叶及总干质量,及降低了闽楠的根茎比。[结论]O_3熏蒸降低了两树种的光合作用,提高了抗氧化能力,最终减少了生物量。根据Pn和生物量,确定闽楠较桢楠对O_3浓度升高更加敏感。两树种间的O_3敏感性差异与气孔导度和抗氧化物质的背景水平及其对O_3浓度升高的响应有关。 相似文献
14.
Yonas Yohannes Olga Shibistova Asferachew AbateMasresha Fetene Georg Guggenberger 《Forest Ecology and Management》2011,261(6):1090-1098
Variability of soil CO2 efflux strongly depends on soil temperature, soil moisture and plant phenology. Separating the effects of these factors is critical to understand the belowground carbon dynamics of forest ecosystem. In Ethiopia with its unreliable seasonal rainfall, variability of soil CO2 efflux may be particularly associated with seasonal variation. In this study, soil respiration was measured in nine plots under the canopies of three indigenous trees (Croton macrostachys, Podocarpus falcatus and Prunus africana) growing in an Afromontane forest of south-eastern Ethiopia. Our objectives were to investigate seasonal and diurnal variation in soil CO2 flux rate as a function of soil temperature and soil moisture, and to investigate the impact of tree species composition on soil respiration. Results showed that soil respiration displayed strong seasonal patterns, being lower during dry periods and higher during wet periods. The dependence of soil respiration on soil moisture under the three tree species explained about 50% of the seasonal variability. The relation followed a Gaussian function, and indicated a decrease in soil respiration at soil volumetric water contents exceeding a threshold of about 30%. Under more moist conditions soil respiration is tentatively limited by low oxygen supply. On a diurnal basis temperature dependency was observed, but not during dry periods when plant and soil microbial activities were restrained by moisture deficiency. Tree species influenced soil respiration, and there was a significant interaction effect of tree species and soil moisture on soil CO2 efflux variability. During wet (and cloudy) period, when shade tolerant late successional P. falcatus is having a physiological advantage, soil respiration under this tree species exceeded that under the other two species. In contrast, soil CO2 efflux rates under light demanding pioneer C. macrostachys appeared to be least sensitive to dry (but sunny) conditions. This is probably related to the relatively higher carbon assimilation rates and associated root respiration. We conclude that besides the anticipated changes in precipitation pattern in Ethiopia any anthropogenic disturbance fostering the pioneer species may alter the future ecosystem carbon balance by its impact on soil respiration. 相似文献
15.
[目的]为研究赤霉素GA4+7对白桦生长的调控机制。[方法]试验利用1个白桦无性系的分株材料,连续2年分别叶面喷施浓度为0.2 g·L~(-1)(T1)、0.4 g·L~(-1)(T2)的GA4+7溶液,对实验苗木的生长情况进行跟踪调查,并对相应顶端生长组织进行转录组测序和差异基因分析。[结果]对2个年份的苗高、地径等性状分析发现,不同处理间苗高与地径的差异均达到显著或极显著水平,GA4+7对高生长有明显的促进作用,2年后的T2白桦苗高较CK提高了19.65%。于6月28日取GA4+7连续处理2年的白桦顶芽开展RNA-seq分析,结果显示:0.4 g·L~(-1)GA4+7(T2)处理与对照(CK)间的差异基因数量最多,即上调表达的基因有181个,下调表达的基因有55个,这些差异基因在叶绿体类囊体膜、红光、远红光及蓝光的细胞响应等方面富集明显。Pathway富集分析显示:氧化磷酸化途径与光合途径中的8条基因呈上调表达,认为施加0.4 g·L~(-1)GA4+7处理后,上述基因的上调表达加快电子传递进程、催化ATP的合成,从而促进白桦光合作用增强,提高苗期生长量。[结论]对白桦外源施加赤霉素GA4+7后,可上调氧化磷酸化途径和光合途径相关基因的表达,进而促进苗木的高和地径生长。研究结果可为白桦生长相关途径基因的克隆提供参考。 相似文献
16.
J.P. Bouillet J.P. Laclau J.L.M. Gonalves M.Z. Moreira P.C.O. Trivelin C. Jourdan E.V. Silva M.C. Piccolo S.M. Tsai A. Galiana 《Forest Ecology and Management》2008,255(12):3918-3930
The sustainability of plantation forests is closely dependent on soil nitrogen availability in short-rotation forests established on low-fertility soils. Planting an understorey of nitrogen-fixing trees might be an attractive option for maintaining the N fertility of soils. The development of mono-specific stands of Acacia mangium (100A:0E) and Eucalyptus grandis (0A:100E) was compared with mixed-species plantations, where A. mangium was planted in a mixture at a density of 50% of that of E. grandis (50A:100E). N2 fixation by A. mangium was quantified in 100A:0E and 50A:100E at age 18 and 30 months by the 15N natural abundance method and in 50A:100E at age 30 months by the 15N dilution method. The consistency of results obtained by isotopic methods was checked against observations of nodulation, Specific Acetylene Reduction Activity (SARA), as well as the dynamics of N accumulation within both species. The different tree components (leaves, branches, stems, stumps, coarse roots, medium-sized roots and fine roots) were sampled on 5–10 trees per species for each age. Litter fall was assessed up to 30 months after planting and used to estimate fine root mortality. Higher N concentrations in A. mangium tree components than in E. grandis might be a result of N2 fixation. However, no evidence of N transfer from A. mangium to E. grandis was found. SARA values were not significantly different in 100A:0E and 50A:100E but the biomass of nodules was 20–30 times higher in 100A:0E than in 50A:100E. At age 18 months, higher δ15N values found in A. mangium tree components than in E. grandis components prevented reliable estimations of the percentage of N derived from atmospheric fixation (%Ndfa). At age 30 months, %Ndfa estimated by natural abundance and by 15N dilution amounted to 10–20 and 60%, respectively. The amount of N derived from N2 fixation in the standing biomass was estimated at 62 kg N ha−1 in 100A:0E and 3 kg N ha−1 in 50A:100E by the 15N natural abundance method, and 16 kg N ha−1 in 50A:100E by the 15N dilution method. The total amount of atmospheric N2 fixed since planting (including fine root mortality and litter fall) was estimated at 66 kg N ha−1 in 100A:0E and 7 kg N ha−1 in 50A:100E by the 15N natural abundance method, and 31 kg N ha−1 in 50A:100E by the 15N dilution method. The most reliable estimation of N2 fixation was likely to be achieved using the 15N dilution method and sampling the whole plant. 相似文献
17.
[目的]随着全球O_3浓度升高,O_3胁迫对植物影响的研究已成为研究的热点之一。我国的相关研究较少,主要以农作物为主,且大多局限在北方地区。本研究探讨O_3胁迫下,亚热带三种楠木幼苗光合作用的变化规律及其可见伤害症状,以期为后续研究提供理论依据。[方法]以一年生亚热带乡土树种桢楠、闽楠和刨花楠幼苗为材料,采用开顶式气室(OTCs),研究低浓度O_3、环境大气、100 n L·L-1O_3、150 n L·L-1O_3处理对光合作用的影响及伤害症状。[结果]研究表明:(1)O_3胁迫下,三种楠木幼苗的光合作用受到一定的抑制,气孔导度和净光合速率的相关性降低,对光合有效辐射的利用范围整体减小,出现了明显的光抑制现象。O_3浓度越高,对桢楠和刨花楠光合作用的抑制效果越明显,而100 n L·L-1O_3处理对闽楠光合作用的抑制效果较150 n L·L-1O_3处理明显。环境大气中的O_3浓度均值较低,但由于其较高的O_3浓度峰值,仍对三种楠木幼苗的光合作用产生了一定的抑制。与环境大气相比,低浓度O_3处理通过消除较高的O_3浓度峰值从而缓解了O_3对光合作用的不利影响。(2)O_3胁迫下,桢楠叶片出现褪绿、黄斑和坏死斑的症状,闽楠叶片出现褪绿、黄斑和水渍的症状,刨花楠叶片出现红褐色斑、水渍、坏死斑、卷曲皱缩、失水萎蔫的症状。三种楠木幼苗叶片的伤害症状随O_3浓度的增加而更明显。[结论]三种楠木幼苗叶片的光合作用均受到O_3的抑制,并出现了伤害症状,可作为O_3污染的指示树种。光合作用对O_3敏感性的关系为:刨花楠闽楠桢楠,其中刨花楠对O_3更敏感,伤害症状也较多样,因此指示O_3污染的效果更好。 相似文献
18.
Marney E. Isaac Jean-Michel HarmandDidier Lesueur Joseph Lelon 《Forest Ecology and Management》2011,261(3):582-588
Acacia senegal, an important leguminous tree in arid and semi-arid environments, has shown promise as a multipurpose species, including gum production and soil fertility improvement, linked with N2-fixation capabilities. Of particular interest are ontogenetic and edaphic effects on A. senegal performance in natural populations. Our research objectives were to investigate the effect of tree age and site phosphorus conditions on (1) tree N2-fixation and (2) soil N and C dynamics in natural stands of A. senegal var. senegal, Baringo District, in the Rift Valley, Kenya. Sites consisted of A. senegal saplings (9 months) and mature A. senegal trees (7 years) along an edaphic gradient of soil P availability. A single-tree neighborhood approach was employed using a two by two factorial design: site conditions [high and low soil P contents] and tree age class [juvenile and mature]. Soil (N and C pools and fluxes) and plant metrics were quantified. A soil transfer experiment was also employed to confirm age and site effects on soil N mineralization. On the high soil P site, A. senegal had significantly lower foliar (15N levels than neighboring non-leguminous species (Balanites aegyptiaca), while foliar δ15N values in A. senegal on the low P site exhibited no significant difference with our reference plant, B. aegyptiaca. Across P sites, B. aegyptiaca had similar foliar δ15N values. These results indicate that the rate of N2-fixation of A. senegal trees, as determined with foliar 15N natural abundance methodology, increased with increasing soil P availability in these natural populations. However, N2-fixation rates declined with age. Although soil texture and soil CO2 efflux did not differ between sites or across ages, soils under mature A. senegal at the high P site exhibited significantly greater total N content and total C content in comparison to soils at the low P site and under juvenile plants. Furthermore, under mature A. senegal trees, soil N mineralization rates were significantly greater as compared to under saplings. Soil transplants confirmed that soil microbial activity may be stimulated under mature trees as N mineralization rates were 2-3 fold greater compared to under A. senegal saplings. Our findings suggest that tree age and soil P availability are important factors in the nitrogen budget of natural populations of A. senegal, determining N2-fixation rates, and potentially influencing soil total N and C pools and soil mineral N. This study provides information regarding the adaptation of A. senegal under differing edaphic conditions thus increasing accuracy of management support for A. senegal populations as productive agroforests. 相似文献