restricted access Development of an in vitro propagation method for the classified New York State–threatened native species Agrimonia rostellata

We developed an in vitro micropropagation protocol for Agrimonia rostellata Wallr. (Rosaceae), a New York State–threatened native plant species. For initial experiments, we investigated methods for disinfection of nodal sections from field-grown plants before transfer to culture medium to generate contaminant-free plant material. Fungal contamination was most prevalent. The only effective treatment was a combination of washes in a detergent solution followed by treatment with 70% ethanol, 10% bleach, plus vacuum infiltration with a solution of the antifungal compound Miconazole. We also found it was necessary to include 20 mg/l Miconazole in the culture medium to prevent fungal contamination. A Murashige and Skoog–based medium supplemented with 0.1 mg/l indole-3-butyric acid (IBA), 5 g/l charcoal, and 7 g/l agar was the only medium tested that resulted in both the development of multiple shoots and rooting. A starting population of 35 contaminant-free, in vitro plants was scaled up to 1013 plants in 6 mo. All rooted plantlets were successfully established in a soilless mix and then transferred to the field. These methods proved to be effective for generating a large population of A. rostellata for replicated field studies to identify the cause(s) of its decline.