Document Type : Research Article
Authors
1
Sari
2
Horticultural Sciences and Landscape Engineering Department, Faculty of Crop Production, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran
3
Horticultural Sciences and Landscape Engineering Department, Faculty of Crop Production, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan
4
Department of Soil Sciences, Faculty of Crop Sciences, Sari Agricultural Sciences and Natural Resources University, Sari
Abstract
Introduction
Bell pepper (Capsicum annuum L.) is one of the most important and widely consumed vegetables in the human diet. Due to its specific physiological characteristics, it is very sensitive to drought stress and water deficit conditions. In recent years, the use of biological compounds as natural elicitors to increase plant resistance to abiotic stresses has received attention. This study aimed to investigate the effect of foliar spraying of melatonin and silicon on physiological and defense indices of bell pepper under drought stress.
Materials and Methods
The experiment was conducted as a split factorial experiment in a completely randomized design with drought as the main factor at three levels (90, 70, and 50 percent of field capacity), the first subfactor, melatonin at three levels (0, 100, and 200 µM), and the second subfactor, silicon at three levels (0, 100, and 200 mg/L) in the greenhouse of Sari Agricultural Sciences and Natural Resources University. The studied traits included antioxidant enzyme activity (catalase, peroxidase, superoxide dismutase), proline, malondialdehyde (MDA) and soluble leaf carbohydrates.
Results and Discussion
The results of analysis of variance showed that the interaction effects of treatments on the levels of catalase and peroxidase enzymes, leaf soluble carbohydrates, proline, and malondialdehyde were significant at the 1% probability level. The highest activity of catalase and peroxidase enzymes was obtained under non-stress conditions and foliar application of 100 μM melatonin and 100 mg/L silicon. Also, the highest proline accumulation was observed at the highest stress level along with foliar application of 200 μM melatonin. Foliar application of silicon at levels of 100 and 200 mg/L and 200 μM melatonin significantly reduced the amount of MDA in stressed plants. The highest amount of leaf soluble carbohydrates was observed in the moderate stress treatment and 100 mg/L silicon foliar application.
Conclusion
These results indicate that simultaneous application of melatonin and silicon effectively improves the tolerance of bell pepper to drought stress by strengthening the antioxidant defense system, increasing the accumulation of osmolytes, and reducing oxidative damage. Therefore, the combined use of these two compounds can be proposed as a biological and low-risk solution for managing drought stress in the sustainable production of this plant.
Introduction
Bell pepper (Capsicum annuum L.) is one of the most important and widely consumed vegetables in the human diet. Due to its specific physiological characteristics, it is very sensitive to drought stress and water deficit conditions. In recent years, the use of biological compounds as natural elicitors to increase plant resistance to abiotic stresses has received attention. This study aimed to investigate the effect of foliar spraying of melatonin and silicon on physiological and defense indices of bell pepper under drought stress.
Materials and Methods
The experiment was conducted as a split factorial experiment in a completely randomized design with drought as the main factor at three levels (90, 70, and 50 percent of field capacity), the first subfactor, melatonin at three levels (0, 100, and 200 µM), and the second subfactor, silicon at three levels (0, 100, and 200 mg/L) in the greenhouse of Sari Agricultural Sciences and Natural Resources University. The studied traits included antioxidant enzyme activity (catalase, peroxidase, superoxide dismutase), proline, malondialdehyde (MDA) and soluble leaf carbohydrates.
Results and Discussion
The results of analysis of variance showed that the interaction effects of treatments on the levels of catalase and peroxidase enzymes, leaf soluble carbohydrates, proline, and malondialdehyde were significant at the 1% probability level. The highest activity of catalase and peroxidase enzymes was obtained under non-stress conditions and foliar application of 100 μM melatonin and 100 mg/L silicon. Also, the highest proline accumulation was observed at the highest stress level along with foliar application of 200 μM melatonin. Foliar application of silicon at levels of 100 and 200 mg/L and 200 μM melatonin significantly reduced the amount of MDA in stressed plants. The highest amount of leaf soluble carbohydrates was observed in the moderate stress treatment and 100 mg/L silicon foliar application.
Conclusion
These results indicate that simultaneous application of melatonin and silicon effectively improves the tolerance of bell pepper to drought stress by strengthening the antioxidant defense system, increasing the accumulation of osmolytes, and reducing oxidative damage. Therefore, the combined use of these two compounds can be proposed as a biological and low-risk solution for managing drought stress in the sustainable production of this plant.
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