Nitrogen Form Alters Sweet Basil Growth and Essential Oil Content and Composition

Abstract

Sweet basil ( Ocimum basilicum L.) plants were grown, until flower buds became visible, in a peat-lite mix and watered daily with a complete nutrient solution with 10 m m N as either or . Ammonium decreased plant height and stem plus petiole dry weight. Leaf blade dry weight was not affected by N form. However, the essential oil content was decreased by 28% with , thereby decreasing the essential oil yield per plant. Although decreased the content (nl·g -1 leaf blade dry weight) of linalool and eugenol, their percentage was not altered. Therefore, the changes in total yield of these individual constituents was simply a reflection of less total extractable essential oil. The total amount of the other major constituents in sweet basil, 1,8-cineole, methyl chavicol, and total sesquiterpenes was not affected significantly. While N form did not alter the percentage of monoterpenes and aromatic polypropa-noides, -N increased the total sesquiterpene percentage. Nitrogen form altered the essential oil content and composition of sweet basil and, therefore, should be considered in nutritional studies with aromatic plants.