Antioxidant Response of Lepidium sativum L. to Metallic Trace Element Stress Under Controlled Mycorrhization...

Abandoned mining sites are major sources of metallic trace element contamination, which negatively affects plant growth, physiological functions, and metabolic activities. In addition, stress caused by metallic trace elements can alter the biosynthesis and accumulation of secondary metabolites. Among the various soil remediation strategies, phytoremediation assisted by arbuscular mycorrhizal fungi (AMF) has emerged as a promising approach. This research examined how effective native AMF are in improving the tolerance of Lepidium sativum L. to lead (Pb) stress. The plants were first cultivated for 2 months in uncontaminated soil before being exposed to 50 mg L^-1 Pb in a controlled environment. A comparative analysis was carried out to assess the impact of mycorrhizal inoculation on plants subjected to Pb exposure versus those that were not. The effects of mycorrhization on growth, physiological performance, and biochemical responses were evaluated. The results demonstrated that mycorrhization positively influenced plant responses to lead stress, as evidenced by improved growth and physiological performance. Compared with non-mycorrhizal plants, mycorrhizal plants exhibited increases of approximately 36% and 17% in chlorophyll a and chlorophyll b contents, respectively, as well as an approximately twofold increase in total soluble sugars. Furthermore, mycorrhization promoted proline accumulation and significantly enhanced catalase activity, with mycorrhizal plants showing an approximately 55% increase compared with non-mycorrhizal plants, indicating a greater capacity to alleviate oxidative stress. Mycorrhization also increased the production of glomalin-related soil proteins in the rhizosphere, further contributing to plant tolerance under lead stress. These findings highlight the potential of indigenous AMF as an eco-friendly and sustainable strategy for enhancing plant tolerance and promoting phytoremediation in lead-contaminated soils.