The role of silver ions in the regulation of the senescence process in Triticum aestivum

Authors: MERT ÖKTEM, YÜKSEL KELEŞ

Abstract: The control of senescence has economic importance due to its effects on parameters such as herbal product quality and shelf life. This study is on the control of induced senescence in Triticum aestivum L. `Gu?n-91' plants with silver nitrate (AgNO₃) treatments. It was observed that some changes that occurred with dark and indole-1-acetic acid (IAA) treatments could be reduced with AgNO₃ treatments. After dark-induced senescence, it was observed in plants that seedling length, relative water content (RWC), chlorophyll, ß-carotene, xanthophylls, total antioxidant capacity, soluble phenol, total soluble protein, catalase (CAT), total superoxide dismutase (SOD), copper-zinc superoxide dismutase (Cu/Zn-SOD) activities, and expression of genes encoding these enzymes declined. After IAA treatments, seedling length, RWC, chlorophyll, ß-carotene, xanthophylls, total antioxidant capacity, soluble phenolics, and soluble protein levels declined, whereas activities of CAT, total SOD, and Cu/Zn-SOD enzymes and expression of Cu/Zn-SOD and CAT genes increased. AgNO₃ (200 mg L^-1 ) applied by spraying onto leaves led to an increase in seedling length, RWC, chlorophyll, ß-carotene, xanthophylls, total antioxidant capacity, soluble phenolics, soluble protein levels, and expression of Cu/Zn-SOD, CAT genes, CAT, SOD, and Cu/Zn-SOD enzyme activities compared to controls. Findings obtained from this study showed that the senescence process was related to changes in the levels of antioxidant compounds and enzymes. It was defined that the role of silver ions in slowing senescence was related to antioxidant defense capacity.

Keywords: Dark, indole-3 acetic acid, silver nitrate, antioxidants, pigments

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