Effects of Different Pre-Sowing Treatments and Soil Substrates on Seed Germination of Salvia przewalskii Maxim

Salvia przewalskii Maxim. is a perennial alpine plant with significant ornamental and medicinal value. However, previous studies have shown that this species has a low germination rate under natural conditions, and its artificial propagation techniques remain unclear. This study aimed to investigate the seed quality and the effects of various pre-sowing treatments (storage, chemical, physical, hormonal, combined) and soil substrates on S. przewalskii germination. The results indicated that S. przewalskii seeds demonstrated high viability (>85%) but exhibited high empty seed rate (45.32%) and physiological dormancy. Compared with the control (20%), dehydration (24.44%), demucilage + dehydration combination (35.56%), storage at 4 °C for 360 (53.33%) and 450 (54.29%) days, and GA3 (44.44–55.56%) treatments significantly enhanced S. przewalskii germination percentages. Demucilage, H2SO4 and KNO3 treatments had negative effects on seed germination, while 6-BA treatment did not significantly improve seed germination. Among tested soil substrates, S. przewalskii seeds pre-chilled for 450 days showed the highest germination rate (71.11%) and optimal seedling growth in peat:vermiculite (3:1), representing the most suitable soil substrate. These findings demonstrate that understanding germination characteristics of S. przewalskii is crucial for developing protocols to enhance germination efficiency that can improve large-scale propagation capacity through shorter germination periods, ultimately enhancing the species regeneration potential and protecting its stability in nature.