Seed priming has a significant effect on seed germination and improves the establishment of crops. In this study, rice seeds (Oryza sativa cv. Shiroodi L.) were primed by different concentrations (0, 0.025, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5 g/l) of Nostoc commune Vauch aqueous extract. Furthermore, seed germination rate, percentage, and seedling growth were examined. The results showed that N. commune extract had a significant positive effect on increasing the percent and rate of seed germination. Indeed, the length of roots and shoots in seedlings obtained from primed seeds with N. commune extract increased compared to those of the seedlings from primed seeds with water. Additionally, the highest seed germination percent and seedling length were obtained by 0.025 g/l N. commune extract. Based on the results, seed germination and seedling growth were not affected by seed priming with N. commune extract at concentrations of more than 0.1 g/l. Therefore, sowing rice seeds with a low concentration of N. commune extract can improve seed germination and seedling establishment.
