Comparative Study of Different Pretreatments on Seed Germination of Juniperus communis L.

Coniferous plants are generally resilient to external environmental conditions and soil types, and they offer a range of ecological and aesthetic benefits. Among coniferous species, Juniperus communis holds a prominent place due to its popularity and suitability for cultivation in the climatic conditions of Azerbaijan. However, its propagation remains challenging due to low germination rates, largely attributed to physiological dormancy associated with its Mediterranean origin, where seeds have adapted to germinate under specific cool and moist conditions. Physical treatments included not only sandpaper abrasion but also exposure to extreme high (60°C) and low (freezer) temperatures. The effectiveness of these pretreatments was assessed using germination parameters such as germination percentage (GP), mean germination rate (MGR), and mean germination time (MGT). Among the tested methods, warm-cold stratification (four weeks at 15°C followed by four weeks at 3°C) yielded the highest germination percentage of 16.7%, significantly outperforming the control (6.7%). In contrast, pretreatments such as prolonged hot water soaking, freezer storage, and mechanical scarification with sandpaper were ineffective, resulting in 0% germination. In conclusion, a comparison with the germination parameters of the control group demonstrated the potential of seed pretreatment as a promising approach for improving conifer propagation and enhancing reproductive outcomes, with warm-cold stratification (15°C for four weeks followed by 3°C for four weeks) emerging as the most effective method.