University of Birjand Journal of Horticulture and Postharvest Research 2588-4883 9 Issue 3 2026 09 01 The effect of seed priming with allantoin and serotonin on germination and growth indices of bitter melon under salt stress 465 480 4098 10.22077/jhpr.2026.9896.1560 EN Masoomeh Amerian Department of Horticultural Sciences and Engineering, Faculty of Agricultural Sciences and Engineering, Campus of Agriculture and Natural Resources, Razi University, Kermanshah, Iran Gholamreza Gohari Department of Horticultural Science, Faculty of Agriculture, University of Maragheh, Maragheh, Iran Saeid Jalali-Honarmand Department of Plant Production and Genetics, Campus of Agriculture and Natural Resources, Razi University, Kermanshah, Iran Sima Panahirad Department of Horticultural Sciences and Landscape Engineering, Faculty of Agriculture, University of Tabriz, Tabriz, Iran Georgia Ntatsi Department of Crop Science, Laboratory of Vegetable Crops, Agricultural University of Athens, Greece Journal Article 2025 08 07 <strong>Purpose:</strong> Salinity stress is one of the most important limiting factors affecting all plant processes, from seed germination to seedling development and plant growth. Seed priming is the most promising seed technique which quickens the germination process and enhances stand establishment. Therefore, seed priming with allantoin and serotonin was performed to investigate their effects on germination and growth of bitter melon seeds under salt. <strong>Research method</strong>: The experiment was conducted as a factorial experiment in a completely randomized design with three replications. The first factor consisted of three concentrations of salinity (0, 50 and 100 mM NaCl) and the second factor included seed priming (48 h) with modulators: control (distilled water), allantoin (1000 μM), serotonin (100 µM) and allantoin + serotonin. After 48 h of applying the priming treatments, the seeds were dried and placed in 9 cm diameter petri dishes lined with filter paper, moistened with the prepared salt solutions, and allowed to germinate at 25 °C. Germination percentage, seed vigor and selected growth characteristics including length, fresh and dry weight of seedling, shoot and root of bitter melon were evaluated. <strong>Findings:</strong> The results revealed that seed germination and seedling growth of bitter melon decreased in line with increasing salt concentrations: on the other hand, seed priming with allantoin (1000 μM) and serotonin (100 µM) alleviated this negative effect of salt stress. It was concluded that allantoin and serotonin, as seed priming agents, positively influenced bitter melon germination under salt stress. These findings may also be applicable to other plants and probably the observed stress tolerance might occur throughout the plant growth period. <strong>Research limitations</strong>: No limitations were identified.<strong> Originality/Value:</strong> Given the medicinal value of bitter melon, solving its germination problem, especially under salt stress conditions, will be of great help to those interested in cultivating this plant. https://jhpr.birjand.ac.ir/article_4098_ab5300cf362a73634b141030fc6c745b.pdf