Munro’s globemallow (Sphaeralcea munroana), endemic to the Great Basin, has suffered significant declines due to a changing climate and invasive species pressure. Despite strong efforts to restore native plants via seed propagation, few cases have been successful. Establishment failure can be attributed to seed germination requirement that are not met during planting. Restoration efforts hinge heavily on the ability to understand the germination strategy of the species. S. munroana occurs primarily at the lower elevations of mountain slopes and in desert valleys. In these environments, seeds may be subject to fire or abrasion in flash floods. Poor ex situ germination in laboratory studies suggest that the seed requires scarification to break dormancy. This study evaluates methods for overcoming seed dormancy and improving germination success.
Results/Conclusions Preliminary research to determine if seed coat impermeability is responsible for poor germination rates has focused on the effect of mechanical scarification and seed imbibition. The results show that physical dormancy plays an important role in germination. Seeds that were pierced exhibited higher germination than the non-pierced treatments. In addition, seed water absorption appears to be slow in S. munroana. Pierced seeds submerged in water reached 25 % of the required moisture content after 24 hours. Conversely, the prolonged water exposure of impermeable (non-pierced) seeds had deleterious effects, resulting in the lowest germination rates. Scarification in the absence of water increased germination compared to the control; however, pierced, water-soaked seeds exhibited the highest germination capacity. This suggests that submergence in water following scarification may be necessary for successful germination. Current research is underway to examine whether heat and fire treatments are sufficient to break dormancy, in order to further understand the germination ecology of S. munroana. The study will examine the effectiveness of wet scarification, submergence in boiling water, burning and dry heating as possible dormancy-breaking techniques for ex situ germination. Successful seed treatment techniques could aid in the restoration of other native species of the Great Basin.
