Ethylene Evolution by Tomato Plants Receiving Nitrogen Nutrition from Urea

Abstract

Urea fertilization of `Heinz 1350' tomato (Lycopersicon esculentum Mill.) in sand or soil culture did not enhance ethylene evolution or restrict growth relative to plants receiving \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathbf{NO}_{\mathbf{3}}^{\mathbf{-}}\) \end{document} whereas \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathbf{NO}_{\mathbf{4}}^{\mathbf{+}}\) \end{document} nutrition doubled the relative rates of ethylene evolution and restricted relative growth. Inhibitors of N transformations in media (nitrapyrin, Np; hydroquinone, HQ; and phenylphosphorodiamidate, PPD) had no apparent stimulator effects on ethylene evolution of plants grown on urea or \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathbf{NO}_{\mathbf{3}}^{\mathbf{-}}\) \end{document} nutrition in sand or soil. Ethylene evolution was enhanced by PPD relative to that by Np or HQ for plants receiving \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathbf{NO}_{\mathbf{4}}^{\mathbf{+}}\) \end{document} nutrition. Each inhibitor had toxic effects on plant growth. Increasing K+ supply from 0 to 8 mm in nutrient solutions decreased ethylene evolution and increased plant growth with urea fertilization. Urea had low phytotoxicity if its hydrolysis to \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathbf{NO}_{\mathbf{4}}^{\mathbf{+}}\) \end{document} was prevented in the media. Chemical names used: p-dihydroxybenzene (hydroquinone); benzenephosphorodiamide (phenylphosphorodiamidate); 2-chloro-6-(trichloromethyl)pyridine (nitrapyrin).