NOVELTY - Generating (M1) a plant having increased nitrogen-dioxide reception ability, involves introducing a nucleic acid encoding a polypeptide having S-nitroso thiol reductase activity to a plant, such that the polypeptide having S-nitroso thiol reductase activity is expressed by the plant.    USE - (M1) is useful for generating a plant having increased nitrogen-dioxide reception ability, where the plant is chosen from Rosaceae plant, Myrtaceae plant, Salicaceae plant, Magnolaceae plant, fig family plant and Brassicaceae plant. The plant generated by (M1) is useful in environmental purification by reducing nitrogen oxide (NO_X) in the inside of the atmospheric environment (claimed), where the nitrogen oxide include nitrogen-dioxide and nitrogen monoxide.    ADVANTAGE - (M1) enables generation of transgenic plant having high nitrogen dioxide reception ability than a wild-type plant, and exhibiting increased yield, thus the nitrogen oxide in the atmospheric and/or soil environmental can be decreased. The reception and assimilation ability of nitrogen dioxide in the plant is increased.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) transgenic plant having increased nitrogen-dioxide reception ability, and being introduced with the nucleic acid encoding the polypeptide having S-nitroso thiol reductase activity, generated by (M1);    (2) reducing nitrogen compound which is reduced nitrogen that cannot be collected by Kjeldahl decomposition method, and non-inorganic nitrogen in a plant, involves introducing nucleic acid encoding polypeptide having S-nitroso thiol reductase activity, to a plant body, such that the polypeptide having S-nitroso thiol reductase activity is expressed; and    (3) promoting nitrogen-dioxide metabolism of a plant, involves introducing nucleic acid encoding polypeptide having S-nitroso thiol reductase activity, to a plant, and/or introducing active inducer of the polypeptide having S-nitroso thiol reductase activity, to the plant that is inheriting the polypeptide, such that the S-nitroso thiol reductase activity inside the plant is reinforced.    DESCRIPTION OF DRAWING(S) - The figure shows the schematic representation of plasmid pIG-GSNOR.