TITLE:
Chemical Composition of the Essential Oil and Nitrogen Metabolism of Menthol Mint under Different Phosphorus Levels
AUTHORS:
Marco A. A. Souza, Osmário J. L. Araújo, Diego M. C. Brito, Manlio S. Fernandes, Rosane N. Castro, Sonia R. Souza
KEYWORDS:
Mentha arvensis L., Lamiaceae, Gas Chromatography, Hydropony, Menthol
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.5 No.15,
July
9,
2014
ABSTRACT: The purpose of this work was to evaluate the effects of different
phosphorus levels (0.05, 0.5, 1 and 2 mM) under nitrogen metabolism and the
essential oil profile of menthol mint (Mentha
arvensis L.). The relationship between the leaf maturity and the essential
oil profile was also explored. The experiment was conducted in a hydroponic
system located in a grow chamber during 41 days and after the harvest, nitrate
reductase activity, and the -N, amino-N, and soluble
sugars levels of each plant part were evaluated. Also the essential oil from
young leaves (6th to 8th node) and adult leaves (3rd to the 5th node) was
analyzed. An uptake mechanism related to the increase in fresh weight of the
roots was promoted with the use of low P levels (0.05 and 0.50 mmol·L-1).
With 1 mmol·L-1 P plants showed in all parts an increased nitrate
reductase activity and high levels of nitrate and amino-N in leaves. Plants
submitted to the lowest P level (0.05 mmol·L-1) presented high
levels of menthol. In leaves from 6th to 8th node (mature leaves) menthol level
was approximately 87% of the essential oil however leaves from the 3rd to the
5th node (young leaves) showed high levels of pulegone, that can be toxic for
humans. The results indicate that the essential oil quality in menthol mint is
influenced by the leaf maturity and the P levels. Also it was showed that the
oil extracted from mature leaves of plants under low P levels has the best
commercial profile.