1- Department of Plant Genetics and Production Engineering, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran
Abstract: (201 Views)
Extended Abstract
Background: Given the contamination of medicinal plants with heavy metals, these plants have high potential in absorbing and transferring them to usable parts. Due to the side effects related to the presence of heavy metals in herbal medicines used in Iran, researchers are today looking for a solution that can reduce the toxic effects of heavy metals in the soil and improve the quality of crops grown in soils contaminated with heavy metals. The use of cost-effective and environmentally safe nanoparticles for the remediation of metal-contaminated soils and biosorption of trace and potentially toxic elements via microalgae or algal extract has received much attention in the past and recently. Therefore, this experiment was conducted to feed fennel with biostimulants, investigate some physiological parameters, reduce the absorption of the heavy metal chromium, and ultimately maintain the quantity and quality of fennel (Foeniculum vulgare).
Methods: This study was conducted as a factorial experiment in a randomized complete block design with three replications under greenhouse conditions in 2023-2024. Treatments included chromium stress at two levels (0 (control) and 100 mg/kg soil) and foliar spray at three levels (control, algal extract at a concentration of 1 mg/L, and selenium nanoparticles at a concentration of 20 mg/L). At the four-leaf stage, foliar spraying was performed at three levels of zero, algal extract (1 mg/L), and selenium nanoparticles (20 mg/L) three times with an interval of 15 days. Ten days after the plant was exposed to the desired stress, the control and treatment plants were sampled to examine the physiological parameters of the plant.
Results: The results of the analysis of variance of the mutual effect of foliar spraying × heavy metal stress were significant regarding the antioxidant enzymes catalase and superoxide dismutase. The results of the mutual effect of selenium nanoparticles × green algae extract were significant for the traits of proline amino acid content and chlorophyll a, chlorophyll b, and total chlorophyll, but there was no significant effect for antioxidant enzymes catalase and superoxide dismutase, electrolyte leakage, and malondialdehyde. The concentrations of malondialdehyde, antioxidant enzymes catalase and superoxide dismutase, proline content, and ion leakage percentage increased significantly under chromium stress, while the content of photosynthetic pigments decreased compared to the control. The application of biostimulants increased the activity of antioxidant enzymes catalase and superoxide dismutase, proline content, and photosynthetic pigment concentrations compared to the control, but the malondialdehyde content decreased compared to the control. In fennel, the activity of catalase and superoxide dismutase enzymes increased in the interaction of chromium with 1 mg/L of the algal extract, 20 mg/L of selenium nanoparticles, and their interaction, respectively, compared to the control. The highest percentage of catalase and superoxide dismutase activity belonged to chromium stress, and the lowest concentration of these enzymes was recorded in the control. The highest activity of antioxidant enzymes under chromium stress after the control was assigned to foliar spraying with algal extract. The interaction effect of selenium nanoparticles and algal extract decreased the content of malondialdehyde and increased photosynthetic pigments. The proline content increased by spraying 20 mg/L of selenium nanoparticles, 1 mg/L of the algal extract, and their interaction compared to the control. As a result, the damage caused by chromium toxic metal stress was moderated by strengthening the antioxidant and photosynthetic system of fennel plants with selenium nanoparticles and algal extract.
Conclusion: In general, among the studied biological stimuli under chromium stress, foliar spraying with algal extract compared to selenium nanoparticles could strengthen the antioxidant system of fennel plants. In this way, it could inhibit the accumulation of free radicals and maintain the integrity of the membrane under chromium stress by reducing the malondialdehyde content.
Background: Given the contamination of medicinal plants with heavy metals, these plants have high potential in absorbing and transferring them to usable parts. Due to the side effects related to the presence of heavy metals in herbal medicines used in Iran, researchers are today looking for a solution that can reduce the toxic effects of heavy metals in the soil and improve the quality of crops grown in soils contaminated with heavy metals. The use of cost-effective and environmentally safe nanoparticles for the remediation of metal-contaminated soils and biosorption of trace and potentially toxic elements via microalgae or algal extract has received much attention in the past and recently. Therefore, this experiment was conducted to feed fennel with biostimulants, investigate some physiological parameters, reduce the absorption of the heavy metal chromium, and ultimately maintain the quantity and quality of fennel (Foeniculum vulgare).
Methods: This study was conducted as a factorial experiment in a randomized complete block design with three replications under greenhouse conditions in 2023-2024. Treatments included chromium stress at two levels (0 (control) and 100 mg/kg soil) and foliar spray at three levels (control, algal extract at a concentration of 1 mg/L, and selenium nanoparticles at a concentration of 20 mg/L). At the four-leaf stage, foliar spraying was performed at three levels of zero, algal extract (1 mg/L), and selenium nanoparticles (20 mg/L) three times with an interval of 15 days. Ten days after the plant was exposed to the desired stress, the control and treatment plants were sampled to examine the physiological parameters of the plant.
Results: The results of the analysis of variance of the mutual effect of foliar spraying × heavy metal stress were significant regarding the antioxidant enzymes catalase and superoxide dismutase. The results of the mutual effect of selenium nanoparticles × green algae extract were significant for the traits of proline amino acid content and chlorophyll a, chlorophyll b, and total chlorophyll, but there was no significant effect for antioxidant enzymes catalase and superoxide dismutase, electrolyte leakage, and malondialdehyde. The concentrations of malondialdehyde, antioxidant enzymes catalase and superoxide dismutase, proline content, and ion leakage percentage increased significantly under chromium stress, while the content of photosynthetic pigments decreased compared to the control. The application of biostimulants increased the activity of antioxidant enzymes catalase and superoxide dismutase, proline content, and photosynthetic pigment concentrations compared to the control, but the malondialdehyde content decreased compared to the control. In fennel, the activity of catalase and superoxide dismutase enzymes increased in the interaction of chromium with 1 mg/L of the algal extract, 20 mg/L of selenium nanoparticles, and their interaction, respectively, compared to the control. The highest percentage of catalase and superoxide dismutase activity belonged to chromium stress, and the lowest concentration of these enzymes was recorded in the control. The highest activity of antioxidant enzymes under chromium stress after the control was assigned to foliar spraying with algal extract. The interaction effect of selenium nanoparticles and algal extract decreased the content of malondialdehyde and increased photosynthetic pigments. The proline content increased by spraying 20 mg/L of selenium nanoparticles, 1 mg/L of the algal extract, and their interaction compared to the control. As a result, the damage caused by chromium toxic metal stress was moderated by strengthening the antioxidant and photosynthetic system of fennel plants with selenium nanoparticles and algal extract.
Conclusion: In general, among the studied biological stimuli under chromium stress, foliar spraying with algal extract compared to selenium nanoparticles could strengthen the antioxidant system of fennel plants. In this way, it could inhibit the accumulation of free radicals and maintain the integrity of the membrane under chromium stress by reducing the malondialdehyde content.
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