title: 15N-labeled ammonium nitrogen uptake and physiological responses of poplar exposed to PM2.5particles.
abstract: Air pollution caused by particulate matter with aerodynamic diameters less than 2.5 μm (PM2.5) is a serious environmental problem. Plants can improve air quality by removing PM2.5from the atmosphere. However, direct evidence of PM2.5absorption and assimilation into plants has not yet been found. In this study, we demonstrate that15NH4+in PM2.5was absorbed by poplar leaves in low and high PM2.5treatment groups (namely, LPT and HPT). Then,15N was subsequently transferred to other parts of the treated seedlings as shown by15N tracing and simulated PM2.5generation.15N and total N contents were the highest in high pollution treatment (HPT), followed by that in low pollution treatment (LPT) and the control. Glutamate dehydrogenase (GDH) contributed more to NH4+assimilation than glutamine synthetase and glutamate synthase in the leaves of treated seedlings. GDH aminating activity was induced upon NH4+exposure whereas GDH deaminating activity was repressed in both LPT and HPT, suggesting that poplar seedlings can alleviate NH4+toxicity by enhancing NH4+assimilation. At the end of PM2.5treatment period, the decreased amino acid content in the treated seedlings was attributed to the probably altered balance of amino acid metabolism. The decline in the net photosynthetic rate (Pn) was accompanied by the decrease in the stomatal conductance in poplar leaves with the extension of PM2.5treatment time, indicating that stomatal limitation is a major reason for Pn reduction. This study may provide novel insights into the relationship between PM2.5pollution and plants.
authors.affiliation: College of Biological Science and Biotechnology, Beijing Forestry University, No. 35, Tsing Hua East Road, Haidian District, Beijing, 100083, China.
authors.forename: Huihong
authors.initials: H
authors.lastname: Guo
authors.affiliation: College of Biological Science and Biotechnology, Beijing Forestry University, No. 35, Tsing Hua East Road, Haidian District, Beijing, 100083, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.affiliation: College of Biological Science and Biotechnology, Beijing Forestry University, No. 35, Tsing Hua East Road, Haidian District, Beijing, 100083, China.
authors.forename: Qingqian
authors.initials: Q
authors.lastname: Liu
authors.affiliation: College of Biological Science and Biotechnology, Beijing Forestry University, No. 35, Tsing Hua East Road, Haidian District, Beijing, 100083, China.
authors.forename: Hailong
authors.initials: H
authors.lastname: An
authors.affiliation: College of Biological Science and Biotechnology, Beijing Forestry University, No. 35, Tsing Hua East Road, Haidian District, Beijing, 100083, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Liu
authors.affiliation: College of Biological Science and Biotechnology, Beijing Forestry University, No. 35, Tsing Hua East Road, Haidian District, Beijing, 100083, China. xiaxl@bjfu.edu.cn.
authors.forename: Xinli
authors.initials: X
authors.lastname: Xia
authors.affiliation: College of Biological Science and Biotechnology, Beijing Forestry University, No. 35, Tsing Hua East Road, Haidian District, Beijing, 100083, China. yinwl@bjfu.edu.cn.
authors.forename: Weilun
authors.initials: W
authors.lastname: Yin
mesh_terms: D000393:Air Pollutants / Q000378:metabolism*; D064751:Ammonium Compounds / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D009587:Nitrogen Isotopes / Q000032:analysis; D010316:Particle Size; D052638:Particulate Matter / Q000378:metabolism*; D018515:Plant Leaves / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D032107:Populus / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D036226:Seedlings / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism
chemical_list: D000393:Air Pollutants; D064751:Ammonium Compounds; D009587:Nitrogen Isotopes; D052638:Particulate Matter; D010940:Plant Proteins; D009584:Nitrogen
keywords: 15N; Enzymes; NH4 + assimilation; PM2.5 exposure; Physiological responses; Poplar seedlings