Tools for conservation ofBalsamorhiza deltoideaandBalsamorhiza sagittata: Karrikin and thidiazuron-induced growth

Wildfires are having both devastating and regenerative impacts on the ecosystems in the Pacific Northwest of North America.Balsamorhiza sagittataandB. deltoidea(balsamroot) are ecologically important species in this region, andB. sagittatapopulations are increasing, whileB. deltoideais critically imperiled. The aim of this research was to establishin vitroprotocols for germination and regeneration ofBalsamorhizaspp. to enable conservation efforts. It was hypothesized that karrikins, which are plant growth regulators released from burning plants during wildfires, would induce seed germination inBalsamorhizaspp. Three karrikins (KAR(1), KAR(2), and KAR(11)) were tested for the ability to enhance germination in these species at two levels (5 or 10 mu M). KAR(2)had the strongest positive effect on germination and induced 47% and 60% germination, respectively, inB. sagittataseeds compared to 14% germination obtained in the control (water agar media). InB. deltoidea, KAR(2)treatment resulted in a germination rate of 73.1% and 100%, compared to 69% in the control. A germplasm collection of seedlings of both species was established for conservation and regeneration experiments. Thidiazuron treatment (10 mu M) induced formation of embryo-like structures in seedlings of bothB. sagittataandB. deltoidea, with regenerants originating from the crown of seedlings.The present study providesin vitromethods for conservation and mass propagation ofBalsamorhizaspecies.