Polyploidy increases tolerance to salt stress in Anise hyssop (Agastache foeniculum [Pursh.] Kuntze)

Maryam Jafarkhani Kermani,Seyyedeh Farahnaz Talebi,Mohammad Jamal Saharkhiz,Yavar Sharafi

doi:10.36253/caryologia-783

Abstract

Salinization is one of the most serious environmental problems in agriculture. Polyploid induction could increase abiotic stress tolerance in plants. In this study, the effect of different NaCl concentrations (0, 50, 100 and 150 mM) was studied on diploid (2x) and tetraploid (4x) plants of anise hyssop (Agastache foeniculum) in vitro. The results indicated that salt stress reduced survival percentage, stem length, and leaf and shoot number in both tetraploid and diploid plants. However, tetraploid plants had better survival and growth rates compared with diploids. The highest antioxidant enzyme activity was observed in the plants treated with 100 mM NaCl, while increasing the salinity to 150 mM NaCl lowered the activity of antioxidant enzymes significantly. Essential oil content in diploid and tetraploid plants decreased as the concentration of NaCl was elevated. Also, salinity stress affected the chemical composition of essential oil in both diploid and tetraploid plants. In conclusion, the results indicated that tetraploids showed greater tolerance to salt stress compared with diploids, and polyploidy might be a useful breeding method in anise hyssop to amplify its tolerance to salt stress under soil salinity.

Highlights

Anise hyssop (Agastache foeniculum) from the family Lamiaceae is as an important medicinal plant
It was observed that the survival percentage of diploid and tetraploid plants decreased with elevation of NaCl concentrations
The results revealed that stem length, leaf and shoot number significantly declined in tetraploid and diploid plantlets of anise hyssop under salt stress

Summary

Introduction

Anise hyssop (Agastache foeniculum) from the family Lamiaceae is as an important medicinal plant. Biotic and abiotic environmental factors, salinity and drought conditions, affect growth parameters, medicinal plants’ survival, and their essential oil yield (Heidari et al 2008, Heydari et al 2020, sharafi et al 2017). High salinity can disturb essential physiological processes due to factors such as water deficits, nutritional imbalance, hyper-osmotic stress, ion imbalance, metabolic disorders, and appearance or disappearance of some proteins which may eventually lead to death (Meng et al 2016). These culminate in reduction of growth, yield, and quality of plants. Several mechanisms have been developed in plants under salt stress, one of which is the control of ion movement across tonoplasts to maintain a low Na+ concentration in the cytoplasm (Brini and Masmoudi, 2012). Apse and Blumwald (2002) showed that plants could use several strategies to keep a high K+/Na+ ratio in the cytosol to control the entry of Na+ ions into and out of cells

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