Optimal Level of Iron and Zinc in Relation to Its Influence on Herb Yield and Production of Essential Oil in Menthol Mint

Abstract

A pot experiment was conducted under glasshouse conditions during 2004 at the Central Institute of Medicinal and Aromatic Plants (CIMAP) in Lucknow. The study presented here was aimed at evaluating the response of Mentha arvensis (cv. Kushal), an essential oil–bearing plant, to different concentrations of zinc (Zn) and iron (Fe) supply with respect to their influence on biomass, oil yield, and oil quality. Suckers of Japanese mint were grown with four graded levels each of Fe and Zn (viz. 0, 5.0, 10.0, 25.0 mg Fe kg⁻¹ and 0, 2.5, 5.0, 15.0 mg Zn kg⁻¹) and a combination of both the elements. The results indicated that the fresh weight, oil content, and chlorophyll content increased significantly with increase in Fe supply; the optimum level was recorded as 10 mg Fe kg⁻¹. Iron uptake increased significantly with increases in its supply. Zinc, when applied singly, showed enhancement in growth parameters, but the effects were nonsignificant. The optimal levels of supply for Zn and Fe in M. arvensis was evaluated to be 5 mg Zn kg⁻¹ and 10 mg Fe kg⁻¹, respectively.

Keywords:

• Essential oil
• iron
• Mentha arvensis
• menthol content
• zinc

Acknowledgments

The authors are thankful to the director of CIMAP for providing necessary facilities during this investigation. The principal author is thankful to Human Resource Development Group, Council of Scientific and Industrial Research, New Delhi, for providing a research associateship.