Effect of Inorganic Nitrogen Supply on Nucleic Acids in Maize Leaves

Supply of inorganic nitrogen in the from of NO₃⁻, NH₄⁺ and NH₄ NO₂ to the maize seedlings increased total RNA and DNA contents of the primary leaves during 8–16 days. Supply of inorganic nitrogen to excised leaf segments from 8-d old dark grown seedlings also, caused some increase in nucleic acid content and this increase was not prevented by the inclusion of tungstate and also to some extent by methionine sulfoximine in the nutrient solution. Decline in RNA and DNA contents in mature (12–16 d) seedlings was prevented to some extent by the supply of nitrogen to intact seedlings and this prevention was not checked by tungstate or methionine sulfoximine. It is suggested that supply of inogranlc nitrogen prevents degradation of nucleic acids in mature leaves.