title: Nitrogen dioxide regulates organ growth by controlling cell proliferation and enlargement in Arabidopsis.
abstract: • To gain more insight into the physiological function of nitrogen dioxide (NO₂), we investigated the effects of exogenous NO₂ on growth in Arabidopsis thaliana. • Plants were grown in air without NO₂ for 1 wk after sowing and then grown for 1-4 wk in air with (designated treated plants) or without (control plants) NO₂. Plants were irrigated semiweekly with a nutrient solution containing 19.7 mM nitrate and 10.3 mM ammonium. • Five-week-old plants treated with 50 ppb NO₂ showed a ≤ 2.8-fold increase in biomass relative to controls. Treated plants also showed early flowering. The magnitude of the effects of NO₂ on leaf expansion, cell proliferation and enlargement was greater in developing than in maturing leaves. Leaf areas were 1.3-8.4 times larger on treated plants than corresponding leaves on control plants. The NO₂-induced increase in leaf size was largely attributable to cell proliferation in developing leaves, but was attributable to both cell proliferation and enlargement in maturing leaves. The expression of different sets of genes for cell proliferation and/or enlargement was induced by NO₂, but depended on the leaf developmental stage. • Collectively, these results indicated that NO₂ regulates organ growth by controlling cell proliferation and enlargement.
authors.affiliation: Department of Mathematical and Life Sciences, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan.
authors.forename: Misa
authors.initials: M
authors.lastname: Takahashi
authors.affiliation: Department of Mathematical and Life Sciences, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan.
authors.forename: Takamasa
authors.initials: T
authors.lastname: Furuhashi
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Ishikawa
authors.affiliation: Department of Life Science, College of Science, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo, 171-8501, Japan.
authors.forename: Gorou
authors.initials: G
authors.lastname: Horiguchi
authors.affiliation: Department of Mathematical and Life Sciences, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Sakamoto
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Tsukaya
authors.affiliation: Department of Mathematical and Life Sciences, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan.
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Morikawa
mesh_terms: D017360:Arabidopsis / Q000166:cytology* / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D018533:Biomass; D002452:Cell Count; D049109:Cell Proliferation / Q000187:drug effects; D048429:Cell Size / Q000187:drug effects; D062951:Endoreduplication / Q000187:drug effects; D035264:Flowers / Q000187:drug effects / Q000502:physiology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D009585:Nitrogen Dioxide / Q000494:pharmacology*; D009929:Organ Size / Q000187:drug effects; D018515:Plant Leaves / Q000166:cytology* / Q000187:drug effects / Q000254:growth & development*; D011003:Ploidies
chemical_list: D009585:Nitrogen Dioxide
keywords: Arabidopsis thaliana; cell enlargement; cell proliferation; early flowering; nitric oxide (NO); nitrogen dioxide (NO2); organ growth