Productive, metabolic and anatomical parameters of menthol mint are influenced by light intensity.

Marco Andre A De Souza,Sonia R De Souza,Renan P Braga,André M Dos Santos,Joecildo F Rocha,Manlio S Fernandes,Rosane N Castro

doi:10.1590/0001-3765202020180321

Marco Andre A De Souza, Sonia R De Souza + Show 5 more

Open Access

https://doi.org/10.1590/0001-3765202020180321

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Abstract

The cultivation of aromatic species to obtain essential oils has great economic importance, presenting an increasing demand from different industrial sectors, especially to menthol mint (Mentha arvensis L.) essential oil, rich in menthol (70-80%). Consortium cultivation has been an important practice in agricultural systems whose land use is necessary, consequently promoting strong competition for light in reduced space. Thus, this study aimed verifying if different light intensities might promote chemical, metabolical and anatomical alterations in menthol mint. Plants were grown in greenhouse at different average of light intensities (137, 254, 406 and 543 µmol photons m2 s1). Samples were collected 43 days after germination and submitted to following analyses: Gravimetric test, photosynthetic pigments, soluble fractions, enzymatic activity, N-total, trichome density and histochemistry and chemometric test based on essential oil chemical profile. Fresh mass gain, trichome density, essential oil content and soluble sugars were positively influenced by light intensity increase. On the other hand, total-N, NO3--N and pigments content have decreased influenced by light intensity increase. In the secretion from the trichomes, phenolic substances were reported, as well as lipophilic ones in the peltate ones. The increase of oxygenated monoterpenes was favored by light intensity decrease.

Highlights

Among various essential oils types, the ones from Mentha genus have been the most requested, mainly from M. arvensis L. with menthol as its principal component (Croteau et al 2005, Shasany et al 2010, Kamatou et al 2013)
In the reason of its high demand, menthol mint essential oil production has been the second greatest worldwide, and second one only to citrus fruits considered as juice industry sub-products (Baser & Buchbauer 2010, Bizzo et al 2009, Kothari 2005)
Menthol mint volatiles biosynthesis exclusively occurs in the secretory cells from the capitate and peltate secretory trichomes, as well as genes involved with menthol route synthesis are expressed in these cells, making this a single site where all biochemical reactions in regarding to volatiles synthesis have occurred (McConkey et al 2000, Sharma et al 2003, Croteau et al 2005, Tiwari 2016)

Summary

Introduction

Among various essential oils types, the ones from Mentha genus have been the most requested, mainly from M. arvensis L. (menthol mint, japanese mint, vique) with menthol as its principal component (Croteau et al 2005, Shasany et al 2010, Kamatou et al 2013). According to Jain (2017) total global production of mint essential oil was 48,000 tons between 2016-2017, of which India contributed 80%, followed by China and Brazil with 9% and 7% respectively. Menthol mint volatiles biosynthesis exclusively occurs in the secretory cells from the capitate and peltate secretory trichomes, as well as genes involved with menthol route synthesis are expressed in these cells, making this a single site where all biochemical reactions in regarding to volatiles synthesis have occurred (McConkey et al 2000, Sharma et al 2003, Croteau et al 2005, Tiwari 2016). The extensive research on the cultivation and elucidation of metabolic pathway responsible for essential oil biosynthesis has made substantial contribution in research focusing on trichomes and production of essential oil (Tiwari 2016)

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