Objective: This study aimed to assess the efficiency of Zinc Oxide (ZnO) nanoparticles in mitigating salinity stress effects in comparison with bulk ZnO, and to examine the influence of different priming durations on chickpea seed germination under salinity conditions.
Method: The study was conducted as a factorial experiment in a completely randomized design with three replications on chickpea (Kasra cultivar). The first factor was the priming agent (1-100 nm ZnO nanoparticles, 40-60 nm ZnO nanoparticles, bulk ZnO, and hydro-priming). The second factor was the priming duration (6, 12, and 24 h), and the third factor was the level of salinity stress (0, 20, 40, and 80 mM NaCl). Key indicators related to germination quality and seedling growth were subsequently assessed.
Results: Salinity stress significantly affected the germination percentage, germination rate, mean germination time, mean daily germination, and seedling vigor weight index. The respective values at 0 and 80 mM NaCl were 98.7% vs. 68.4%, 15.6 vs. 10.4 germinated seeds per day, 2.11 vs. 2.39 days, 12.3 vs. 8.56 seeds per day, and 5466 vs. 1853. Salinity stress also significantly increased the root-to-shoot length ratio. Seed priming with 1-100 nm ZnO nanoparticles significantly increased seedling dry weight, shoot dry weight, root dry weight, and consequently, the seedling vigor index compared to other zinc forms and hydro-priming. Furthermore, this treatment reduced the percentage of abnormal seedlings to 20.7% under 80 mM NaCl. Priming durations of 12 and 24 h were superior to 6 h, resulting in a significant increase in seedling and shoot length, seedling and shoot weight, and the seedling vigor length index.
Conclusions: Salinity stress had significant adverse effects on germination and seedling growth characteristics and increased the proportion of abnormal seedlings. However, seed priming exerted a more pronounced positive effect on improving seedling growth and reducing the number of abnormal seedlings. Among the priming treatments, ZnO nanoparticles (1-100 nm) with a priming duration of 12 h were the most effective in enhancing seedling growth and the seedling vigor index, providing clear guidance for future research and applications.
Highlights
- Seed priming at a salinity level of 20 mM significantly alleviated the adverse effects of salinity on seedling growth parameters.
- Seed priming of chickpea with zinc nanoparticles (1 to 100 nm) was more effective than other seed priming methods in promoting seedling growth.
- A priming duration of 12 h was identified as the optimal treatment for maximizing seedling growth and vigor index.
