Morshedloo M, Farhadi H, Ahmadi H, Maggi F. Determining the Salt Tolerance Threshold of Mentha suaveolens Ehrh. under Gamma-Aminobutyric Acid (GABA) Influence. مرتع 2024; 17 (4) :622-639
URL:
http://rangelandsrm.ir/article-1-1222-en.html
Department of Horticultural Science, Faculty of Agriculture, University of Maragheh, Maragheh
Abstract: (672 Views)
Background and objectives: Salinity stress poses a significant challenge worldwide, particularly in arid and semi-arid regions, impacting the physiological processes and secondary metabolites of medicinal plants like Mentha suaveolens Ehrh. Distributed in humid rangelands, this species is notably affected by environmental salinity rise and excessive exploitation. Therefore, enhancing or preserving the quality and quantity of its metabolites under natural or cultivated conditions, including irrigation with unconventional saline waters, using modern methods, becomes imperative. Recently, gamma-aminobutyric acid (GABA), a biomolecule known to induce plant tolerance in various physiological processes, has been explored to optimize conditions and enhance plant performance under stress. This study aimed to model and evaluate the effects of GABA concentrations on the secondary metabolites and physiological characteristics of Mentha suaveolens under varying salinity levels.
Methodology: The influence of GABA concentrations ranging from 0 to 2.4 mM on secondary metabolites and physiological traits of apple mint species under salinity levels of 0 to 150 mM NaCl was assessed in a greenhouse at the Faculty of Agriculture, Maragheh University, during the year 1401. At the end of the trial period, parameters such as biomass performance, relative water content of aerial organs, and secondary metabolites including flavonoids, phenols, DPPH radical scavenging activity, proline, malondialdehyde (MDA), carotenoids, chlorophyll, and essential oil content were evaluated. Statistical analysis and Principal Component Analysis (PCA) were performed on the collected data.
Results: Salinity stress led to reductions in root and shoot dry weight, piperitone oxide content, relative water content, chlorophyll content, and PSII maximum quantum yield (Fv/Fm). Conversely, malondialdehyde (MDA), total flavonoids, and DPPH radical scavenging activity increased under salinity. Application of GABA mitigated the negative effects of salinity stress, with the most significant changes observed under higher salinity (150 mM) and GABA (2.4 mM) levels. PCA analysis accounted for 90.58% of changes under different treatments. DPPH activity, piperitone oxide, and essential oil content showed the highest gradients, indicating their sensitivity to salinity levels and GABA application. Notably, NaCl(0)-GABA(0) and NaCl(0)-GABA(2.4) treatments exhibited the most significant combined effects on plant physiological characteristics. Salinity stress had varying effects on phenol and biomass content, while GABA application showed minimal to moderate effects on these parameters. Overall, severe salinity stress (>120 mM NaCl) adversely impacted plant performance and evaluated characteristics.
Conclusion: Salinity stress significantly altered functional characteristics of Mentha suaveolens, inducing metabolic changes to cope with or enhance tolerance to salinity stress. Modeling indicates that optimal GABA application could maintain or improve medicinal performance under moderate salt stress conditions. However, extreme salinity stress (120 to 150 mM) adversely affects plant performance, suggesting limited efficacy of GABA application in such conditions.
Type of Study:
Research |
Subject:
General Received: 2023/09/9 | Accepted: 2024/02/21 | Published: 2024/02/29