Seed dormancy and greenhouse propagation of arrowleaf balsamroot (Balsamorhiza sagittata) and silverleaf phacelia (Phacelia hastata var. hastata)
Bujak, Charissa Maria
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Native plant material, defined by the United States Forest Service, includes all indigenous terrestrial and aquatic plant species that evolved naturally in a defined ecosystem. Native plant material is important for horticultural and restoration purposes; however, propagation protocols for many Montana native plant species remains unknown. This study addressed the following: greenhouse propagation, seed dormancy classification, and seed-dormancy release treatments for arrowleaf balsamroot (Balsamorhiza sagittata) and silverleaf phacelia (Phacelia hastata var. hastata). Additionally, an assessment was completed to better understand current challenges, successes of the Montana native plant market. In this study gibberellic acid (GA3) significantly increased final germination of arrowleaf balsamroot to 81% + or = 2%. Utilizing the Baskin and Baskin (1998, 2004) seed dormancy classification scheme, arrowleaf balsamroot seed dormancy was classified as: 1) nondeep physiological dormancy type 2, 2) intermediate physiological dormancy type 2, and 3) deep physiological dormancy type 1 and 3. Following the Schewienbacher (2011) reclassification scheme, arrowleaf balsamroot seeds were indicative of physiological deep dormancy type 3. In the greenhouse, fertilizer rates up to 200 mg nitrogen/L (20-10-20 NPK of Jack's Professional Peat Lite Special TM) resulted in positive shoot growth but beyond 100 mg nitrogen/L reduced the root-to-shoot value. The Ray Leach Cone-tainer TM was an effective container type. For silverleaf phacelia, 87% + or = 5% germination was achieved within four days with scarification for at least 90 seconds. After 1 year of storage at 5 + or = 1°C, following the Baskin and Baskin (1998) classification scheme, silverleaf phacelia seed dormancy was classified as 1) nondeep physiological dormancy type 1, 2, and 5, and 2) intermediate physiological dormancy type 1 and 2. Addressing nondeep physiological dormancy type 5 would be most effective in breaking seed dormancy. In the greenhouse, fertilizer rates beyond 50 mg nitrogen/L (20-10-20 NPK of Jack's Professional Peat-Lite Special) resulted in positive shoot growth but beyond 50 mg nitrogen/L reduced root mass. The 4-inch square pot was an effective container type. A survey of 30 Montana native plant growers indicated a demand for native plants in the Montana nursery industry. However, more work needs to be completed to develop and stabilize the native plant market.