Interactive effects of air pollutants and atmospheric moisture stress on aspen growth and photosynthesis along an urban-rural gradient
Interactive effects of air pollutants and atmospheric moisture stress on aspen growth and photosynthesis along an urban-rural gradient
复制标题
城乡梯度空气污染物和大气水分胁迫对白杨生长和光合作用的交互影响
DOI：
10.1016/j.envpol.2020.114076
复制
发表时间：
2020
影响因子：
8.9
通讯作者：
Liu Lingli
中科院分区：
文献类型：
--
作者：
Wang Zhenhua;Wang Chengzhang;Wang Bin;Wang Xin;Li Jing;Wu Jin;Liu Lingli
大气污染对树木生长有显著的影响，并与气象条件有协同作用。华北地区提供了一个研究植物生长如何在不同气象条件下对空气污染做出反应的自然实验，快速的经济增长导致了严重的空气污染，气候变化增加了干旱胁迫。以欧洲山杨（Populus euramericanaNeva.）作为“植物生长计”，我们进行了三个试验，监测沿着北京市城乡梯度大气污染物原位暴露期间白杨叶片光合作用和茎生长。采用逐步模型选择法选择最佳多元线性模型，采用分组回归法估计大气污染物、大气水分胁迫及其交互作用对白杨叶片光合作用和生长的影响。结果表明，臭氧（O3）和水汽压亏缺（VPD）抑制叶片光合作用和茎的生长。O3和VPD的交互作用产生协同效应：随着O3浓度的增加，VPD对叶片光合作用和茎生长的负面影响变得更加严重。我们还发现，氮（N）沉降对茎生长有积极的影响，这可能是由于冠层N吸收的增加，虽然这一假设需要进一步的研究证实。气溶胶负荷的积极影响可能是由于漫辐射施肥效应造成的。随着O3浓度的增加和干旱风险的增加，气溶胶和氮沉降量减少，华北地区大气污染对树木生长的负面影响可能加剧。此外，O3与VPD的相互作用可能导致生态系统生产力的进一步降低。
Atmospheric pollution could significantly alter tree growth independently and synergistically with meteorological conditions. North China offers a natural experiment for studying how plant growth responds to air pollution under different meteorological conditions, where rapid economic growth has led to severe air pollution and climate changes increase drought stress. Using a single aspen clone (Populus euramericanaNeva.) as a ‘phytometer’, we conducted three experiments to monitor aspen leaf photosynthesis and stem growth duringin situexposure to atmospheric pollutants along the urban-rural gradient around Beijing. We used stepwise model selection to select the best multiple linear model, and we used binned regression to estimate the effects of air pollutants, atmospheric moisture stress and their interactions on aspen leaf photosynthesis and growth. Our results indicated that ozone (O3) and vapor pressure deficit (VPD) inhibited leaf photosynthesis and stem growth. The interactive effect of O3and VPD resulted in a synergistic response: as the concentration of O3increased, the negative impact of VPD on leaf photosynthesis and stem growth became more severe. We also found that nitrogen (N) deposition had a positive effect on stem growth, which may have been caused by an increase in canopy N uptake, although this hypothesis needs to be confirmed by further studies. The positive impact of aerosol loading may be due to diffuse radiation fertilization effects. Given the decline in aerosols and N deposition amidst increases in O3concentration and drought risk, the negative effects of atmospheric pollution on tree growth may be aggravated in North China. In addition, the interaction between O3and VPD may lead to a further reduction in ecosystem productivity.