Comparative study of Conocarpus erectus and Phoenix dactylifera as plant biomonitors of particulate matter pollution in Kuwait over three residential areas

This study evaluated two widely distributed ornamental species, buttonwood and palm for their effectiveness as biomagnetic monitors over three different land use classes (urban, suburban and industrial land classes).Three experimental sites were classed based on functionalities, population numbers and vicinity to emission sources (Al-Mansouriya ‘urban’ residential area, Al-Shuwaikh Residential area ‘industrial' and Al-Rumaithya ‘suburban’ residential area. Date palm and buttonwood were selected as they are easily identifiable and widely distributed throughout Kuwait’s landscape. Sampling was conducted in September 2017 and continued for a month. At each selected study site, 100 samples of both species were randomly selected and collected. Sampling height was not specified for this experimental set up, as it was not the main goal of this research. Each sample consists of five leaves from the same randomly chosen tree. Leaves were selected on: size similarity, visual absence of abnormalities or signs of nutritional deficiencies, using a 3m telescopic pruning lopper. Leaves were selected at an azimuth angle of 70 degrees. Plants, coordinates, height, distance from the nearest road and distance from the closest plant were recorded. A variety of magnetic measurements were applied to the leaf samples to enable the quantification of magnetic concentration within selected sites and also identify grain size variations and magnetic mineralogy. Prior to magnetic analysis Image J software was used to determine total surface area (cm2) to attain NRM, SIRM, HIRM values normalized for leaf area. Samples were then air dried for 5 days, packed in A4 size cling film under went magnetic measurement using a using an AGICO magnetometer. Leaf abaxial and adaxial micro-morphological characteristics were analyzed using scanning electron microscopy (SEM) imaging using an environmental scanning electron microscope (FEG-ESEM) equipped with an energy dispersive X-Ray (EDX) detector. Descriptive statistics (SPSS, (21.0)). The rest of the Statistical analyses were conducted using (R 3.5.1) software. Kolmogorov-Smirnov normality test (K-S) was applied to determine the most suitable statistical test. A General Linear Model (GLM) analysis of variance (ANOVA) was employed to determine the interaction between the two subject factors: tree species and land class use assess main effects and interactions . For multiple comparisons, Bonferroni´s tests were applied. A Multivariable model was used adjust and obtain true effects of variables. An (ANCOVA) model was applied to determine significant difference between variables and assess their effects on parameters. Additionally, the effects of species and land class as well as interactions terms were adjusted and corrected. One-way Anova models assessed homogeneity of the land classes and species. Spatial variation of magnetic parameters was determind by Inverse Distance Weighted technique (IDW) using ArcGIS.本研究选取两种广泛分布的观赏树种——悬铃木（buttonwood）与椰枣（Date palm），评估其作为生物磁监测指示物种的有效性，研究针对城市、郊区与工业用地三类土地利用类型展开。 本研究依据用地功能、人口规模及与排放源的邻近程度，设置三处实验样地：Al-Mansouriya“城市”居民区、Al-Shuwaikh“工业”居民区以及Al-Rumaithya“郊区”居民区。选择这两种树种的原因在于其易于识别，且广泛分布于科威特全境的景观植被中。 采样工作于2017年9月启动，持续时长为一个月。在每处选定的样地中，随机采集两种树种各100份样本。本次实验未设定采样高度，因该因素并非本研究的核心目标。每份样本取自同一棵随机选取的树木的5片叶片，采样时遵循以下标准：叶片大小相近、外观无异常或营养缺乏迹象，采样工具为3米伸缩修枝剪，且采样方位角为70度。同时记录植株坐标、树高、距最近道路的距离以及距最近同种植株的距离。 针对叶片样本开展多类磁学测量，以量化各实验样地内的磁性物质浓度，同时识别磁性晶粒尺寸变化与矿物组成。磁学分析前，使用Image J软件计算叶片总表面积（单位：cm²），以便对天然剩余磁化强度（NRM）、饱和等温剩余磁化强度（SIRM）与硬剩磁（HIRM）值进行叶面积归一化处理。随后将样本风干5天，用A4尺寸保鲜膜包裹后，使用AGICO磁力仪开展磁学测量。 使用配备能量色散X射线（EDX）探测器的场发射环境扫描电子显微镜（FEG-ESEM），通过扫描电子显微镜（SEM）成像分析叶片远轴面与近轴面的微观形态特征。 描述性统计分析采用SPSS（21.0）软件完成，其余统计分析使用R 3.5.1软件进行。首先通过柯尔莫哥洛夫-斯米尔诺夫正态性检验（K-S检验）确定适配的统计方法。采用一般线性模型（GLM）的方差分析（ANOVA），探究两个主体因子——树种与土地利用类型的交互作用，以评估主效应与交互效应。多重比较采用邦费罗尼（Bonferroni）检验。构建多变量模型以校正并获取变量的真实效应。采用协方差分析（ANCOVA）模型探究变量间的显著差异，并评估其对各参数的影响。此外，对树种、土地利用类型及其交互项的效应进行校正与修正。单因素方差分析模型用于评估土地利用类型与树种的组间同质性。利用ArcGIS的反距离加权法（IDW）确定磁学参数的空间分布特征。