title: Atmospheric nitrogen dioxide gas is a plant vitalization signal to increase plant size and the contents of cell constituents.
abstract: We report the unexpected novel finding that exogenously supplied atmospheric NO2 at an ambient concentration is a plant vitalization signal to double shoot size and the contents of cell constituents. When seedlings of Nicotiana plumbaginifolia were grown for 10 wk under natural light and irrigation with 10 mm KNO3 in air containing (+NO2 plants) or not containing (-NO2 plants) 15NO2 (150 +/- 50 ppb), shoot biomass, total leaf area, and contents per shoot of carbon (C), nitrogen (N), sulphur (S), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), free amino acids and crude proteins were all approximately 2 times greater in +NO2 plants than in -NO2 plants. In mass spectrometric analysis of the 15N/14N ratio, it was found that NO2-derived N (NO2-N) comprised < 3% of total plant N, indicating that the contribution of NO2-N to total N was very minor. It thus seems very likely that the primary role of NO2 is as a multifunctional signal to stimulate plant growth, nutrient uptake and metabolism.
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.forename: Makiko
authors.initials: M
authors.lastname: Nakagawa
authors.forename: Atsushi
authors.initials: A
authors.lastname: Sakamoto
authors.forename: Chieko
authors.initials: C
authors.lastname: Ohsumi
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Matsubara
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Morikawa
mesh_terms: D001272:Atmosphere; D009585:Nitrogen Dioxide / Q000378:metabolism*; D018515:Plant Leaves / Q000254:growth & development; D018517:Plant Roots / Q000254:growth & development; D018520:Plant Shoots / Q000254:growth & development; D036226:Seedlings / Q000254:growth & development; D014026:Nicotiana / Q000254:growth & development* / Q000378:metabolism*
chemical_list: D009585:Nitrogen Dioxide