Journal Article

Metabolic activities, biochemical, and physiological processes in Mentha pulegium L. induced by drought stress and application of 5-aminolevulinic acidf

Shahhoseini, Reza, Farhadi, Nasrin, Angourani, Hossein Rabbi

2025

Overview

Pennyroyal ( Mentha pulegium L.) is a valuable medicinal plant, renowned for its diverse biological and therapeutic effects, which are largely attributed to its wide range of secondary metabolites, such as terpenoids and phenolic compounds. Currently, water deficit, as a major growth-limiting factor for many medicinal plants, poses one of the most significant challenges in plant production. A factorial experiment, based on a completely randomized design (CRD) with three replications, was conducted to assess the effects of foliar application of 5-aminolevulinic acid (ALA) on the growth, physiological attributes, and biochemical responses of M. pulegium under a gradient of drought stress intensities. The experimental treatments comprised four levels of drought stress (100%, 75%, 50%, and 25% of field capacity) and four concentrations of 5-aminolevulinic acid (ALA) (0, 5, 10, and 15 µM). The accumulation of malondialdehyde (MDA), hydrogen peroxide (H₂O₂), proline, glycine betaine, and total phenols, as well as the activities of catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) enzymes, were elevated in response to increasing drought intensity. A decline in relative water content, photosynthetic pigment levels, stomatal conductance, Rubisco enzyme activity, and photosynthetic rate with increasing stress levels resulted in reduced plant growth. Foliar application of ALA significantly mitigated the accumulation of hydrogen peroxide and lipid peroxidation (as measured by malondialdehyde content) in pennyroyal plants. This protective effect was mediated by an enhancement in the accumulation of antioxidant compounds, including total phenols and essential oils, coupled with increased activity of antioxidant enzymes such as catalase, peroxidase, and superoxide dismutase. Furthermore, ALA application, particularly at a concentration of 10 µM, alleviated the detrimental effects of water deficit on photosynthesis by enhancing photosynthetic pigment content, stomatal conductance, and Rubisco enzyme activity. The enhanced drought tolerance observed in pennyroyal following ALA application is primarily attributed to a significant boost in the plant’s antioxidant capacity. This enhanced capacity effectively protects the photosynthetic apparatus from oxidative damage. Consequently, the resultant improvement in photosynthetic efficiency supports better growth performance under drought stress conditions.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Accumulation / Acids / Agriculture / Aminolevulinic acid / Aminolevulinic Acid - pharmacology / antioxidant activity / Antioxidant capacity / Antioxidants / betaine / Biochemical compounds / Biological effects / Biomass / Biomedical and Life Sciences / Biosynthesis / Catalase / Catalase - metabolism / Chemical properties / Conductance / Dehydration / Drought / Drought resistance / Drought Resistance - drug effects / Drought Resistance - physiology / drought tolerance / Droughts / Enzymatic activity / Enzyme activity / Enzymes / Essential oils / Field capacity / Flowers & plants / foliar application / Foliar applications / Glycine / Glycine betaine / growth performance / Hardiness / Hedeoma / Herbal medicine / Hydrogen peroxide / Hydrogen Peroxide - metabolism / Iran / Irrigation / Leaves / Life Sciences / Lipid peroxidation / Lipids / Malondialdehyde / Malondialdehyde - metabolism / Medicinal plant / Medicinal plants / Mentha - metabolism / Mentha - physiology / Mentha pulegium / Metabolites / Moisture content / Oxidative stress / Pennyroyal / Peroxidase / Peroxidation / Phenolic compounds / Phenols / Phenols - metabolism / Photosynthesis / Photosynthesis - drug effects / Photosynthesis - physiology / Photosynthetic apparatus / Photosynthetic pigments / Physiological aspects / Physiological effects / Physiology / Pigments / Plant growth / Plant Leaves - metabolism / Plant production / Plant Sciences / Plants / Plants, Medicinal - metabolism / Plants, Medicinal - physiology / proline / protective effect / Ribulose-bisphosphate carboxylase / Secondary metabolites / Seeds / Stomata / Stomatal conductance / Stress, Physiological - physiology / Superoxide dismutase / Superoxide Dismutase - metabolism / Terpenes / terpenoids / therapeutics / Tree Biology / Water content / Water deficit / water stress