title: Differential assimilation of nitrogen dioxide by 70 taxa of roadside trees at an urban pollution level.
abstract: In order to screen for the best species for mitigating nitrogen dioxide (NO2) by plants at urban levels, we investigated assimilation of nitrogen dioxide by 70 taxa of woody plants that are mostly utilized as roadside trees. They were fumigated with 15N-labeled NO2 at 0.1 microl l(-1) for 8h, and the amount of reduced nitrogen derived from NO2 (in mg Ng(-1) dry weight) in the leaves (designated NO2 assimilation capability hereafter) were determined. Data were analyzed in the comparison with the previously reported ones obtained at 4 microl l(-1) NO2. Among the 70 taxa, the value of NO2 assimilation capability differed by a factor of 122 between the highest (Prunus yedoensis; 0.061) and the lowest (Cryptomeria japonica; 0.0005). Based on the analysis of NO2 assimilation capability values at 0.1 and 4 micro l(-1) NO2, the 70 taxa of woody plants appeared to be classified into four types; those of high NO2 assimilation and high NO2 resistance, those of high NO2 assimilation but low NO2 resistance, those of low NO2 assimilation and low NO2 resistance, and those of low NO2 assimilation but high NO2 resistance. The first, second, third and fourth types include 13, 11, 35 and 11 taxa, respectively. The broad-leaf deciduous trees may have advantages of high biomass and fast growth as compared with woody plants of other habits. Thus, four broad-leaf deciduous species, Robinia pseudo-acacia, Sophora japonica, Populus nigra and Prunus lannesiana, were concluded here to be the best phytoremediators for the urban air.
authors.affiliation: Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, 1-3-1, Kagamiyama, Higashi-Hiroshima 739-8526, Japan. mtakahas@sci.hiroshima-u.ac.jp
authors.forename: Misa
authors.initials: M
authors.lastname: Takahashi
authors.forename: Asa
authors.initials: A
authors.lastname: Higaki
authors.forename: Masako
authors.initials: M
authors.lastname: Nohno
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Kamada
authors.forename: Yukio
authors.initials: Y
authors.lastname: Okamura
authors.forename: Kunio
authors.initials: K
authors.lastname: Matsui
authors.forename: Shigekazu
authors.initials: S
authors.lastname: Kitani
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Morikawa
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002947:Cities; D007564:Japan; D009584:Nitrogen / Q000032:analysis; D009585:Nitrogen Dioxide / Q000032:analysis / Q000378:metabolism*; D014197:Trees / Q000378:metabolism*
chemical_list: D000393:Air Pollutants; D009584:Nitrogen; D009585:Nitrogen Dioxide