Synthetic polyploid induction influences morphological, physiological, and photosynthetic characteristics in Melissa officinalis L

Rohit Bharati; Aayushi Gupta; Pavel Novy; Lucie Severová; Karel Šrédl; Jana Žiarovská; Eloy Fernández-Cusimamani

doi:10.3389/fpls.2023.1332428

Synthetic polyploid induction influences morphological, physiological, and photosynthetic characteristics in Melissa officinalis L

Front Plant Sci. 2023 Dec 14:14:1332428. doi: 10.3389/fpls.2023.1332428. eCollection 2023.

Authors

Rohit Bharati¹, Aayushi Gupta², Pavel Novy³, Lucie Severová⁴, Karel Šrédl⁴, Jana Žiarovská⁵, Eloy Fernández-Cusimamani¹

Affiliations

¹ Department of Crop Sciences and Agroforestry, The Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, Prague, Czechia.
² Department of Botany and Plant Physiology, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Prague, Czechia.
³ Department of Food Science, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Prague, Czechia.
⁴ Department of Economic Theories, Faculty of Economics and Management, Czech University of Life Sciences Prague, Prague, Czechia.
⁵ Faculty of Agrobiology and Food Resources, Slovak University of Agriculture in Nitra, Nitra, Slovakia.

Abstract

Melissa officinalis L., a well-known herb with diverse industrial and ethnopharmacological properties. Although, there has been a significant lack in the breeding attempts of this invaluable herb. This study aimed to enhance the agronomical traits of M. officinalis through in vitro polyploidization. Nodal segments were micropropagated and subjected to oryzalin treatment at concentrations of 20, 40, and 60 mM for 24 and 48 hours. Flow cytometry, chromosome counting, and stomatal characteristics were employed to confirm the ploidy level of the surviving plants. The survival rate of the treated explants decreased exponentially with increasing oryzalin concentration and duration. The highest polyploid induction rate (8%) was achieved with 40 mM oryzalin treatment for 24 hours. The induced tetraploid plants exhibited vigorous growth, characterized by longer shoots, larger leaves, and a higher leaf count. Chlorophyll content and fluorescence parameters elucidated disparities in photosynthetic performance between diploid and tetraploid genotypes. Tetraploid plants demonstrated a 75% increase in average essential oil yield, attributed to the significantly larger size of peltate trichomes. Analysis of essential oil composition in diploid and tetraploid plants indicated the presence of three major components: geranial, neral, and citronellal. While citronellal remained consistent, geranial and neral increased by 11.06% and 9.49%, respectively, in the tetraploid population. This effective methodology, utilizing oryzalin as an anti-mitotic agent for polyploid induction in M. officinalis, resulted in a polyploid genotype with superior morpho-physiological traits. The polyploid lemon balm generated through this method has the potential to meet commercial demands and contribute significantly to the improvement of lemon balm cultivation.

Keywords: Melissa officinalis; chromosome doubling; crop improvement; essential oil; oryzalin; polyploid induction; polyploidization.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This research was funded by the Internal Grant Agency, grant number 20233105, Faculty of Tropical AgriSciences, Czech University of Life Sciences in Prague.