Studies on the Nitrogen Metabolism in Tobacco Plants. A.

Abstract
Nitrate N accounts for 40-70% of the total N and the rest is composed mostly of amino and alkaloid N. Amides and basic amino acids compose a large part of the amino and amide N. Among the amino acids and amides glutamine is highest in content, and asparagine, lysine leucine and serine follow. Topping increased the alkaloid contents in the sap but decreased the amino acid N as compared with untopped plants.