Department of Ecology, Complutense University, Madrid, Spain.
Department of Ecology, Complutense University, Madrid, Spain.
J Environ Manage. 2018 Apr 15;212:440-449. doi: 10.1016/j.jenvman.2017.12.049. Epub 2018 Feb 22.
The growing number of road vehicles is a major source of regional and global atmospheric pollution increasing concentrations of CO in the air, and levels of metals in air and soil. Nevertheless, the effects of these pollutants on plants growing at roadsides are poorly documented. We carried out an observational study of unmanipulated plants growing by the road, to identify the morpho-physiological responses in a perennial grass Dactylis glomerata. Firstly, we wanted to know the general effect of traffic intensity and ambient CO and its interactions on different plant traits. Accordingly, we analyzed the photosynthetic response by field A/Ci Response Curves, SLA, pigment pools, foliar nitrogen, carbohydrates and morphological traits in plants at three distances to the road. Secondly, we wanted to know if Dactylis glomerata plants can accumulate metals present on the roadside (Pb, Zn, Cu, and Sr) in their tissues and rhizosphere, and the effect of these metals on morphological traits. The MANCOVA whole model results shown: 1) a significant effect of road ambient CO concentration on morphological traits (not affected by traffic intensity, P >0.05), that was mainly driven by a significant negative relationship between the inflorescence number and ambient CO; 2) a positive and significant relationship between ambient CO and the starch content in leaves (unaffected by traffic intensity); 3) a reduction in J (electron transport rate) at high traffic intensity. These lines of evidences suggest a decreased photosynthetic capacity due to high traffic intensity and high levels of ambient CO. In addition, Pb, Cu, Zn and Sr were detected in Dactylis glomerata tissues, and Cu accumulated in roots. Finally, we observed that Dactylis glomerata individuals growing at the roadside under high levels of CO and in the presence of metal pollutants, reduced their production of inflorescences.
道路上行驶的车辆越来越多，这是导致区域和全球大气污染的一个主要原因，致使空气中 CO 浓度不断增加，空气中的金属和土壤中的金属含量也在不断上升。尽管如此，这些污染物对道路两旁植物的影响仍鲜有记录。我们对生长在道路旁未经人为干预的植物进行了观察研究，以确定多年生草类多花黑麦草的形态和生理响应。首先，我们想了解交通强度、环境 CO 及其相互作用对不同植物特性的一般影响。因此，我们分析了距道路 3 个不同距离处植物的光合作用响应（通过田间 A/Ci 响应曲线、SLA、色素库、叶片氮、碳水化合物和形态特征）。其次，我们想知道多花黑麦草植物是否能在其组织和根际中积累道路旁存在的金属（Pb、Zn、Cu 和 Sr），以及这些金属对形态特征的影响。MANCOVA 整体模型结果表明：1）环境 CO 浓度对形态特征有显著影响（不受交通强度影响，P＞0.05），主要是由于花序数量与环境 CO 之间存在显著负相关；2）环境 CO 与叶片中淀粉含量呈正相关且显著（不受交通强度影响）；3）在高交通强度下 J（电子传递速率）降低。这些证据表明，由于交通强度高和环境 CO 水平高，导致光合作用能力下降。此外，在多花黑麦草组织中检测到 Pb、Cu、Zn 和 Sr，Cu 在根部积累。最后，我们观察到在高 CO 水平和存在金属污染物的情况下，生长在道路旁的多花黑麦草个体减少了花序的产生。
