نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه مهندسی کشاورزی-مجتمع آموزش عالی میناب-دانشگاه هرمزگان-بندرعباس
2 گروه مهندسی کشاورزی، مجتمع آموزش عالی میناب، دانشگاه هرمزگان، بندرعباس، ایران،
3 فارغ التحصیل اگرواکولوژی، دانشگاه فردوسی مشهد
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and objectives: Among abiotic stresses, salinity is a major global constraint that adversely affects plant physiology, growth, and productivity. Salinity impairs seed germination and early seedling development primarily through osmotic stress that limits water uptake and through ionic toxicity caused by excessive accumulation of Na⁺ and Cl⁻ ions. Consequently, developing approaches to mitigate the adverse effects of salinity during the early stages of plant growth is of considerable interest. This study aimed to evaluate the effects of seed exposure duration to ultrasound waves on germination and seedling responses of cotton under salt stress conditions in laboratory and greenhouse environments.
Materials and methods: The experiment consisted of a factorial combination of three ultrasound exposure durations (0, 20, and 40 min) and three salinity levels (0, 50, and 100 mM). Following ultrasound treatment, seeds were cultured under two growth conditions: Petri dishes (laboratory) and seedling trays (greenhouse). Germination indices and seedling growth traits were recorded. The experiment was conducted as a completely randomized design with three replications in both the laboratory and greenhouse at the Minab Higher Education Center.
Results: Ultrasound treatment and salinity level significantly affected germination indices and seedling traits. Mean comparison analysis indicated that a 20-min ultrasound treatment resulted in the highest germination percentage, whereas the lowest germination occurred in seeds without ultrasound exposure. At 50 mM salinity, the 20-min ultrasound treatment substantially alleviated the inhibitory effects of salt stress, resulting in the highest germination percentage at this salinity level. Germination percentage increased as ultrasound exposure duration increased from 0 to 20 min but declined when exposure was extended to 40 min. Increasing salinity levels significantly reduced emergence percentage. The longest mean germination time was observed in the non-irradiated and 40-min ultrasound treatments, while the shortest mean germination time occurred with the 20-min ultrasound treatment. Correlation analysis between laboratory and greenhouse data revealed significant positive relationships between germination percentage and emergence percentage, germination rate and emergence rate, and germination index and emergence index.
Conclusion: The results demonstrate that the effectiveness of ultrasound seed treatment under saline conditions is strongly dependent on both salinity intensity and exposure duration. Appropriate ultrasound pretreatment can partially mitigate salt-induced inhibition of germination and early seedling growth; however, excessive exposure may have adverse effects. These findings suggest that careful optimization of ultrasound parameters is essential and highlight the potential of ultrasound technology as a novel and effective seed pretreatment method for improving cotton establishment under salinity stress.
کلیدواژهها [English]
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