با همکاری انجمن فیزیولوژی گیاهی ایران
نوع مقاله : مقاله پژوهشی
نویسنده
دانشگاه آزاد اسلامی-واحد شوشتر
کلیدواژهها
عنوان مقاله English
نویسنده English
Introduction
Cowpea (Vigna unguiculata L.) is considered a strategic legume in the agricultural systems of tropical and subtropical regions across Africa, Asia, South America, parts of southern Europe, and the United States . Due to its high nutritional value—including protein (approximately 25%), carbohydrates (approximately 64%), vitamins, and fiber—it plays a vital role in ensuring food security and improving soil fertility . This crop is recognized for its drought and heat tolerance and, owing to its high rate of nitrogen fixation, is capable of thriving in soils with low fertility (Sadeghipour, 2017). Nevertheless, its yield potential in many agricultural areas is constrained by environmental stresses, particularly soil and irrigation water salinity.Salinity stress is one of the most significant abiotic constraints limiting agricultural productivity worldwide, particularly in arid and semi-arid regions. In cowpea (Vigna unguiculata L.), salinity disrupts the physiological processes during germination, leading to reduced seedling vigor, stunted growth, and decreased crop yield. Seed priming, a pre-sowing treatment involving controlled hydration, has emerged as a promising technology to mitigate abiotic stresses. By initiating metabolic activities without radicle emergence, priming can enhance membrane integrity and antioxidant systems, thereby improving germination efficiency under stressful environments. This study aimed to evaluate the effectiveness of hydropriming and halopriming (using NaCl, CaCl₂, and CaSO₄) on two local bean cultivars (Mashhad and Kamran) under different salinity levels.
Materials and Methods
This research was carried out in the laboratory of the Seed Science and Technology Department of Islamic Azad University, Shushtar branch in 2024-2025. The study was conducted using two local cultivars of cowpea: 'Mashhad' and 'Kamran'. The seeds were subjected to three levels of salinity (0, 85, and 170 mM NaCl) to simulate different stress intensities. The priming treatments were applied for 4 hours at 25°C in total darkness. The priming methods included: 1. Hydropriming (HP): Soaking in distilled water. 2. Halopriming (HAP): Soaking in 80 mM concentrations of NaCl, CaCl₂, and CaSO₄. Control groups consisted of non-primed seeds. The experiment carried out based on a completely random design with 3 replications. The evaluated parameters included germination percentage (GP), germination speed (GS), final germination percentage, radicle length (RL), hypocotyl length (HL), epicotyl length (EL), and Seedling Vigor Index (SVI).
Results and Discussion
The results demonstrated a significant interaction between salinity levels and priming techniques across all measured parameters. Germination Dynamics: It was observed that increasing salinity levels (up to 170 mM) significantly decreased the germination percentage in non-primed seeds. However, priming treatments effectively counteracted this decline. For instance, under moderate salinity (85 mM NaCl), halopriming with NaCl in the 'Kamran' cultivar increased the final germination percentage from 63.33% to 86.66%, representing a substantial improvement of 20.33%. Under severe salinity (170 mM NaCl), the 'Kamran' cultivar achieved a 37% germination rate with hydroprimed seeds, whereas the 'Mashhad' cultivar reached 86%. The Germination Speed (GS) was significantly higher in all primed groups, with hydropriming showing the highest acceleration in germination rates for both cultivars. Regarding Hypocotyl (HL) and Epicotyl (EL) Lengths parameters were significantly affected by salinity, genotype, and the S × P interaction (P < 0.01). Priming helped maintain better shoot development compared to non-primed seeds under stress. While salinity and genotype had significant effects on radicle length, the direct effect of priming on RL was found to be non-significant in this specific study, suggesting that priming primarily affects the metabolic readiness and shoot elongation rather than radical extension under these specific conditions. The SVI was highly sensitive to both salinity and priming (P < 0.01). Although salinity significantly reduced the SVI, priming treatments—particularly those involving CaSO₄ and NaCl—significantly enhanced the vigor of the seedlings, ensuring a more robust start for the plants in saline soils.
Conclusion
This study confirms that seed priming is an effective strategy to alleviate the negative impacts of salinity on cowpea germination and early seedling growth. Both hydropriming and halopriming (specifically with 80 mM NaCl and CaSO₄) demonstrated significant success in improving germination percentage and seedling vigor in both the 'Mashhad' and 'Kamran' cultivars. The ability of CaSO₄ to trigger germination in the 'Mashhad' cultivar even under 170 mM salinity suggests that calcium-based halopriming is a particularly potent tool for managing extreme saline environments. These findings offer a practical approach for farmers to improve crop establishment in salinity-prone areas.
کلیدواژهها English
