| چکیده انگلیسی مقاله |
Extended abstract
Introduction: Salinity stress leads to the excessive production of reactive oxygen species, which at high levels can cause oxidative damage, disrupt membrane lipid functions, inactivate enzymes, and hinder metabolic activities in plants. Salinity affects seedling growth through osmotic stress, ionic toxicity, deficient absorption of essential nutrients and water, production of free radicals, destruction of the cell membrane, and reduced cell division. Utilizing pretreatment methods serves as a simple approach to mitigate the adverse effects of environmental stress. Seed pretreatment induces biochemical changes, such as the activation of enzymes involved in cellular metabolism, inhibition of metabolism, and improved water absorption, thereby aiding the germination process. This study aims to assess the impact of pretreatment on germination characteristics, activity of certain hydrolytic enzymes, and the glyoxylate cycle in marigold seedlings under salinity stress.
Materials and Methods: The experiment was conducted using a factorial design based on a completely randomized arrangement with three replications at the University of Mohaghegh Ardabili in 2022. Experimental treatments included four salinity levels (0, 50, 100, and 150 mM sodium chloride) and four pretreatment methods (control with distilled water, pretreatment with salicylic acid at 100 mg/L, gibberellin at 20 mg/L, and chitosan at 0.8% w/v, dissolved in 1% acetic acid).
Results: The findings indicated that salinity reduced germination percentage, mean daily germination, petiole length, and seedling dry weight. However, pretreatment with salicylic acid, gibberellin, and particularly chitosan significantly improved these parameters. The germination coefficient, radicle length, and seedling fresh weight in chitosan-pretreated groups without salinity were approximately 75%, 68%, and 34% higher compared with the control (distilled water) and 150 mM salinity treatments, respectively. Additionally, the activities of amylase, protease, and malate synthase in chitosan-pretreated groups without salinity increased by approximately 82%, 46%, and 70%, respectively, compared to the control and 150 mM salinity.
Conclusions: The results of this research demonstrate that seed pretreatment using salicylic acid, gibberellin, and especially chitosan is an effective strategy for enhancing germination indices and the activity of certain hydrolytic enzymes and the glyoxylate cycle, thereby alleviating the detrimental effects of salinity on marigold seedlings and promoting their growth.
Highlights: - Seed pretreatment with salicylic acid, gibberellin, and especially chitosan significantly improved germination indices of marigold seeds under salinity conditions.
- This pretreatment enhanced the enzymatic activity of amylase, protease, and malate synthase.
- Chitosan pretreatment exhibited superior effects on germination indices and biochemical characteristics.
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