城市交通道路绿化植物滞尘效应研究

以石家庄市7条主要交通干路,11种常见绿化植物为研究对象,研究比较了不同绿化植物的滞尘量,构建了绿化植物单位叶片面积累积滞尘量与滞尘时间的对数曲线方程,并通过滞尘时间、叶表微形态结构、叶片性状、叶面距地高度及交通道路环境等因素分析了绿化植物综合滞尘能力的差异。结果表明:金叶女贞、大叶黄杨综合滞尘能力最强,平均累积滞尘量达到4.0g/m2以上;棣棠、海棠、迎春、紫叶李的滞尘能力居中,单位面积累积滞尘量介于2.0~4.0g/m2之间;毛白杨、大叶女贞、白丁香滞尘能力一般,单位面积累积滞尘量介于1.0~1.5g/m2之间;七叶树、月季滞尘能力相对较弱,单位面积累积滞尘量分别为0.996g/m2和0.730g/m2。通过2个独立样本T检验分析表明,城市交通道路车流量及周边环境的差异对植物的滞尘效果产生了显著的影响。     

山西太原常绿植物滞尘能力差异性及叶面微结构

以太原市4种常绿植物叶片为试材,采用称重法测定了山西省太原市4种常绿植物叶片单位质量和单位叶面积滞留细颗粒物质量,并利用扫描电子显微镜观察叶表微结构,对常绿植物叶片滞尘能力进行了分析比较,以期阐释常绿植物叶表微结构特征对空气细颗粒物吸附能力的影响机制.结果 表明:不同植物单位质量和单位叶面积滞尘量均存在一定差异,滞尘范围分别为0.012～0.035μg·cm-2和2.39～8.52μg·cm-2.叶表沟槽宽度差异可能是不同植物吸附细颗粒物不同的主要原因之一,叶片沟槽过窄不易滞留细颗粒物,而沟槽越深细颗粒物吸附量越大.气孔宽度与叶表细颗粒物吸附效果存在一定相关性.灌木单位叶面积对细颗粒物的滞尘量高于草本;叶表面沟槽较宽、较深的金叶女贞(Ligus-trum×vicaryi)和小叶黄杨(Buxus microphylla)相比其它参试植物单位叶面积可滞留更多PM2.5等细颗粒物.     

扬州城市道路部分绿化树种滞尘效应研究

以扬州市城区干道绿化树种为试材,研究了滞尘指标以及树种、地段、季节因素等对叶面滞尘效应评价的影响。结果表明:叶片滞尘量测定值在一定程度上可以反映客观环境空气中的颗粒物含量,以文昌路的最大、校园次之、公园最小,其与采样地点的影响密切相关;常绿灌木的叶片滞尘量较大,则表现为对地面粉尘的拦截能力强。因受树种单叶面积大小、树冠密集度、整株叶量多少和叶片组织结构等制约,各滞尘量指标间不尽一致。乔木树种中:单叶滞尘量(mg)与单位面积滞尘量(g/m2)反映一致,为广玉兰悬铃木银杏枫杨女贞香樟,干重滞尘量(mg/g)变化较大,为枫杨银杏悬铃木广玉兰女贞香樟;综合各项指标比较,以落叶树种的滞尘能力占优势,仅广玉兰的单位面积滞尘量表现最高。灌木树种中:单叶滞尘量(mg)、干重滞尘量(mg/g)均以珊瑚树最大,而单位面积滞尘量(g/m2)以小叶黄杨最大。叶片滞尘量的季节性变化与秸秆焚烧等大气污染的动态变化具有明显的相关性,其中:广玉兰以5月值最高,余皆以10月值最高。     

新疆南疆三种果树叶表面微形态结构与滞尘能力比较

以新疆轮台县3种果树(苹果、核桃、杏)叶片为试材,对其滞尘量和叶片表面微形态结构进行观测,探究了3种果树叶片平均滞尘量在不同时间段和不同高度的变化及叶表面结构与其滞尘量的关系。结果表明:不同果树的滞尘量不同,其中苹果叶片的滞尘量最大,可达到5.295mg·cm~(-2),杏叶片的滞尘量最低,仅为2.697mg·cm~(-2)。叶片滞尘量随时间延长而增加(P0.01);不同高度的滞尘量差异极显著(P0.01),叶片平均滞尘量依次为1m[(1.716±0.800)mg·cm~(-2)]2m[(1.217±0.355)mg·cm~(-2)]3m[(0.950±0.362)mg·cm~(-2)]。叶片表面观察结果表明,果树叶片表面在微形态结构上存在明显差异,滞尘能力较强的苹果叶表面结构粗糙,具有绒毛;滞尘能力较弱的杏叶表面结构光滑,无毛。叶表面结构不同,滞尘能力也出现明显差异,说明滞尘能力与叶表特征密切相关。     

二十种园林绿化树木滞尘量比较

为了揭示焦作城市绿化树种的滞尘规律,选择工业区、文教区和闹市区3个功能区的20种绿化树木对其进行叶片滞尘量分析.结果表明:枇杷、小叶黄杨和臭椿单位面积滞尘能力较强,垂柳、紫叶小檗、紫荆、合欢和白蜡相对较弱,悬铃木、国槐、毛白杨、紫叶李、银杏、大叶黄杨、构树、火棘、栾树、椤木石楠、紫薇和大叶女贞居中.对单叶滞尘量而言,枇杷、毛白杨、紫荆和悬铃木最大,构树、臭椿、紫薇、火棘、紫叶李、大叶黄杨、大叶女贞、国槐、垂柳和栾树居中,银杏、紫叶小檗、合欢、白蜡、椤木石楠和小叶黄杨最小.     

南宁市兴宁区14种常见道路绿化植物滞尘能力探讨

本研究主要从昆仑大道、嘉和城周边道路以及校园道路上各选择14中常见的绿化植物来测定其叶片滞尘量。从植物单叶滞尘量、单位面积滞尘量、滞尘量随时间变化的规律、植物叶面特征、同一植物在不同地点滞尘量分析所调查植物的滞尘能力,为本地区道路绿化植物的应用提供参考。     

邢台市区园林阔叶植物滞霾效果研究

采用显微计数法对邢台市区常见园林阔叶植物叶片滞霾效果进行比较研究。结果表明,不同植物种间滞霾效果存在显著差异。从滞霾数量来看,灌木植物呈现出强、弱分化的现象,迎春滞霾数量最多,月季滞霾量较少;从吸附灰霾颗粒直径大小来看,紫叶李对PM10以下的灰霾颗粒吸附率比较高;从灰霾数量和直径综合来看,滞霾效果表现最好的是榆树。植物滞霾能力并不是由单一因素决定的,具有枝条茂密紧凑、叶片小而硬、叶柄短小、叶表面粗糙有绒毛、能分泌粘液等特征的植物滞霾能力较强。此外,叶片的粗糙程度对吸附灰霾颗粒的大小有一定筛选作用。     

金叶女贞滞尘效应研究

以金叶女贞为试材,研究比较了其在不同环境条件下滞尘量的差异及蒙尘后的生理响应.结果表明:金叶女贞在所选择地点的平均单位面积滞尘量大小顺序依次为:建筑区＞商业区＞工业区＞校园区.对叶面尘粒径分析表明,叶面尘中滞留的颗粒物中大多数是TSP,同时对PM10和PM2.5均有一定量的吸收.随着叶片蒙尘时间的延长,相对含水量出现先下降后上升的趋势,比叶重出现动态变化的趋势,脯氨酸的含量则有增加的趋势.     

西安市绿化树种滞尘效应初探

针对西安市植物的滞尘能力,选取重度污染区（大明宫建材市场、小寨）、中度污染区（土门商厦、长安立交）和轻污染区（西安工程大学临潼校区）作为对照区,其中分别采集法国梧桐、国槐、石楠、腊梅等8-10种植物的叶片,采用重量称量法对其雨后第1、第3、第5天的滞尘量的差值进行滞尘能力的大小测量。结果表明：通过计算重度污染区与清洁区之间的净相对滞尘通量,得出不同地区同一树种的滞尘能力大小。乔木滞尘能力：法国梧桐（0．2669g／m2）〉国槐（0．1284g／m^2）〉红叶李（0．1990g／m^2）〉垂柳（0．1104g／m^2）〉樱花（0．0881g／m^2）;灌木滞尘能力：石楠（0．2081g／m^2）〉腊梅（0．1726g／m^2）〉五角枫（0．1054g／m^2）〉紫荆（0．0605g／m^2）〉冬青（0．0428g／m^2）。故在大气重污染区进行绿化时,应该考虑那些在重污染区叶片具有高度滞尘能力的植物种类;同一地区不同树种的滞尘能力大小,乔木：法国梧桐〉国槐〉红叶李〉垂柳〉樱花;灌木：石楠〉腊梅〉五角枫〉紫荆〉冬青;其滞尘能力的大小决定于各树种的自身生长情况和生理特征。要合理配置绿化树种,以达到滞尘效果最佳。     

北京常见树种滞留大气颗粒物能力研究

为研究北京常见树种滞留颗粒物的能力,以北京20种常见树种及部分2~3年生苗为试材,通过叶片采样、电镜扫描、能谱分析、图像处理、脯氨酸含量测定等方法,对常见树种的滞尘能力进行系统分析。结果表明:2~3年生苗滞尘效果方面存在一定的差异,滞尘能力较高的为麦李和毛樱桃,较差的为接骨木、香椿和毛桃;由于实际造林立地条件的不同,不同立地条件下树种滞尘能力不同,该差异与其叶表面微形态结构密切相关,不同树种叶表面形成不同的沟槽、突起、小室,沟槽越密集,越深,越有利于滞留大气颗粒物;单位面积滞尘量较高的树种其脯氨酸含量也较高;能谱分析表明,树种所附着的颗粒物为PM2.5和PM10的尘土,部分元素来自于汽车尾气的排放。     

Particle resuspension from leaf surfaces: Effect of species,leaf traits and wind speed

Particles deposited on leaf surfaces can be resuspended back into the atmosphere, thus generating pollution diffusion and hazarding to human health. The net amount of particles resuspended depends on leaf traits and weather conditions, such as speed wind and leaf roughness. However, little is known about the influence of leaf traits of different tree species on particle resuspension under certain conditions. In this study, we chose 6 typical greening tree species from Northeast China and focused on four-leaf traits: roughness, contact angle, stomatal density, and groove width. The wind tunnel was used to measure particle resuspension from leaf surfaces at different wind speeds (1, 2, 3 m/s) and test duration (10, 20, 30 min). Subsequently, we investigated the correlation between particle resuspension and leaf traits. The results indicated that Abies holophylla had the highest resuspension fraction (61.38%), followed by Salix babylonica (58.05%), Populus alba (54.21%), Juniperus chinensis (53.59%), and Pinus tabuliformis (50.51%), while Robinia pseudoacacia displayed the lowest particle resuspension fraction (32.02%). Particle resuspension rates of the tested species ranged from (8.24 ± 0.53) × 10⁻⁴/s to (2.65 ± 0.51) × 10⁻⁴/s, which was found to increase with wind speed enhancement and decrease with duration extension. With increasing the wind speed, the Pinus tabuliformis, and Juniperus chinensis were more efficient than Salix babylonica, and Populus alba in avoiding particle resuspension. Roughness and stomatal density were a significant negative correlation with particle resuspension rates, which demonstrates that the leaf surface traits can affect the particle resuspension process. Finally, our results suggest that the main factors influencing particle resuspension from leaf surfaces are wind speed, roughness, and stomatal density, which will provide a scientific foundation for pollution diffusion in future studies.     

The influence of plant morphological structure characteristics on PM2.5 retention of leaves under different wind speeds

Exploring the relationships between plant morphological structures and PM_2.5 (particulate matter < 2.5 µm in diameter) retention on leaf surfaces and determining the key factors will help to screen tree species with high-efficiency PM reduction and improve the air purification function of green spaces. PM_2.5 retention experiments were conducted in a wind tunnel using 1800 branches from 30 species with different morphological structures under wind speeds of 1, 3.5, and 8 m/s. Eight comprehensive variables (PC1–PC8) of plant morphological structure were extracted by principal component analysis, and their relationships with PM_2.5 retention and the main influencing factors were explored by stepwise regression models. Under all of the wind speeds, the totality characteristic (PC1) (composite variable of factors including volume and total surface area) and surface area/weight density (PC2) of plant branches and leaves were the two most significant influencing factors, and they had negative effects. In addition to the aforementioned two common key factors, the leaf size (PC5) and surface roughness (PC7) were the two key positive factors at wind speeds of 1 and 3.5 m/s, while the number of branches and leaves (PC3 and PC4, respectively) were the two key positive factors at a wind speed of 8 m/s. Generally speaking, with the increase of wind speed, the effect of leaf morphological characteristics on PM_2.5 retention decreased, while the crown structure characteristics became more significant. Compared with leaf morphological characteristics, the crown morphological structure variables had greater variability and a greater impact on PM_2.5 retention. Crown morphological structure should be given more importance in screening high-efficiency PM retention tree species.     

Air pollution removal through deposition on urban vegetation: The importance of vegetation characteristics

Urban vegetation has the potential to improve air quality as it promotes pollutant deposition and retention. Urban air quality models often include the effect vegetation have on pollution dispersion, however, processes involved in pollution removal by vegetation are often excluded or simplified and does not consider different vegetation characteristics. In this systematic review, we analyze the influence of the large interspecies variation in vegetation characteristics to identify the key factors affecting the removal of the major urban pollutants, particulate matter (PM) and nitrogen dioxide (NO₂) from the air through vegetation deposition. The aim is to identify key processes needed to represent vegetation characteristics in urban air quality modelling assessments.We show that PM is mainly deposited to the leaf surface, and thus representation of characteristics affecting the aerodynamics from canopy down to leaf surface are important, such as branch/shoot complexity and leaf size, leaf surface roughness and hairiness. In addition, characteristics affecting PM retention capacity, resuspension and wash-off, include leaf surface roughness, hairiness and wax content. NO₂ is mainly deposited through stomatal uptake, and thus stomatal conductance and its responses to environmental conditions are key factors. These include response to solar radiation, vapour pressure deficit and soil moisture.Representation of these vegetation characteristics in urban air quality models could greatly improve our ability to optimize the type and species of urban vegetation from an air quality perspective.     

黄顶菊蒸腾速率日变化及影响因子的灰色关联度分析

应用TPS-1便携式光合测定仪,对入侵植物黄顶菊叶片的蒸腾速率和影响因子的日变化同步进行了测定,并采用灰色关联度分析的方法研究了黄顶菊叶片蒸腾速率与影响因子的关系.结果表明:黄顶菊蒸腾速率日进程呈“双峰”型,且峰值达1.05 mmol·m-2·s-1.灰色关联度分析表明,气孔导度RS、叶室温度Tl、量子通量密度PFD是影响蒸腾速率的主导因子.     

欧李叶片秋季光合作用日变化研究

利用Li-6400便携式光合作用测定系统测定了2a生欧李叶片秋季光合生理生态特性及环境因子日变化,并采用相关分析和逐步回归法探讨了欧李叶片净光合速率的主要影响因子。结果表明:欧李净光合速率(Pn)日变化曲线为双峰型,第1峰(峰值为7.96μmol.m-2.s-1)出现在10:00左右,第2峰(峰值为6.26μmol.m-2.s-1)出现于15:00左右,具有一定程度的光合"午休"现象。欧李Pn与气孔导度(Gs)、蒸腾速率(Tr)以及光合有效辐射(PAR)显著正相关,而与胞间CO2浓度(Ci)及空气相对湿度(RH)显著负相关。其光合"午休"现象原因主要为气孔关闭引起的气孔限制因素。Gs与Ci为影响欧李Pn的关键因子,Gs影响最大、Ci次之。     

两种化学型广藿香叶显微特征比较

以6个不同产地的2种化学型广藿香叶片为试材,采用数码显微系统对叶片的多种显微特征进行观察比较,采用SPSS 21.0、MEGA 7、SIMCA 14.1软件进行脉岛数、栅表比、气孔指数、非腺毛数、头状腺毛数、盾状腺毛数显微常数的方差分析、聚类分析和主成分分析试验,以期为广藿香叶片显微特征与化学型分型的研究及广藿香品质评价提供参考依据。结果表明:2种化学型广藿香叶表皮细胞形状、表皮细胞长宽比、气孔大小及类型相近;叶缘、叶长宽比、垂周壁形状、表皮细胞大小、栅表比、脉岛数、气孔指数、非腺毛数、头状腺毛数、盾状腺毛数差异显著,可以作为区分广藿香不同化学型的评判指标;四会、高州、雷州、阳春4个产地的广藿香归为一类,均为醇型,莲塘、龙洞产地归为一类,均为酮型。     

成都市二十五种屋顶绿化木本植物的降温增湿能力研究

为了提高屋顶绿化植物配置的科学性,筛选降温增湿能力强的绿化植物,对成都市屋顶绿化适应性强的25种木本植物进行了叶片蒸腾速率的测定。结果表明:彩叶植物的降温增湿能力高于绿叶植物,差异极显著(Sig.=0.002);落叶植物显著高于常绿植物(Sig.=0.022);乔木显著高于灌木(Sig.=0.030),观花植物显著高于观叶植物(Sig.=0.022),其中龙牙花、木芙蓉、龙爪槐、紫叶李、贴梗海棠、海栀子等木本植物具有较高的蒸腾速率,降温增湿能力强,可为成都市屋顶绿化植物选择提供参考。     

Growth, stomata aperture, biochemical changes and branch anatomy in mango (Mangifera indica) cv. Chokanan in response to root restriction and water stress

Mango production is often subject to space and tree size management pressures among growers. This study found that root restriction contributed to reduced leaf expansion, thus inhibiting the growth of mango trees. There was even less leaf expansion under water stress conditions. Under well-watered conditions, restricted roots considerably reduced stomatal conductance and leaf water potential compared to control root growth. More rapid reductions in stomatal conductance and leaf water potential occurred under restricted root and water stress conditions compared to control trees. Leaf proline concentrations and abscisic acid (ABA) levels increased as a result of root restriction and water stress but decreased with re-watering. Re-watering also increased stomatal conductance, leaf water potential and peroxidase accumulation in plants with both restricted and non-restricted root growth. Anatomical studies of cross sections of secondary branches showed that root restriction and water stress brought about various changes: compacted cells, as estimated by epidermis thickness and area, as well as by cortex thickness, but with increases in schelerenchyma thickness, phloem and xylem thickness, schelerenchyma area, and pith area and diameter. These results suggest that reduction of soil volume and water stress could effectively control tree size through physiological and morphological changes; thereby bringing higher sustainable returns per hectare and greater effectiveness in orchard management.     

土壤铅胁迫对旱柳生长及相关生理特性的影响

采用盆栽试验方法研究了不同铅胁迫浓度下旱柳幼苗的生长及相关生理指标的变化。结果表明:随着重金属铅胁迫浓度的增加,旱柳的比叶重、株高与地径生长受到抑制;叶绿素含量及根系活力呈下降的趋势;叶片游离脯氨酸含量与细胞膜透性呈逐渐增加趋势。在浓度为300mg/kg时,游离脯氨酸、细胞膜透性及根系活力与对照相比达到显著差异(P<0.05);在浓度600mg/kg时,株高、地径与对照相比达到极显著差异(P<0.01);叶绿素a与对照相比达到显著差异(P<0.05);不同铅胁迫浓度对叶绿素b、叶绿素a/b值没有显著的影响。