Poster

         Physiology

Growth of Platanthera dilatata Orchid Seeds with Different Nitrogen Sources

Presenting Author
Sofia Baez
Description
Orchids use their relationships with mycorrhizae in the soil around them to facilitate germination in the wild. In the lab, the seeds can be germinated in petri plates using an agar-based medium supplemented with elements like carbohydrates, nitrogen, potassium, and phosphorus to replicate the nutrients they receive in the wild. In this experiment, the germination of seeds of a temperate terrestrial orchid, Platanthera dilatata was measured over time to evaluate the effect of different nitrogen sources on their growth. Varying nitrogen sources were tested because although most orchid species respond to environmental factors at the germination stage, few of these species have been studied in-depth to identify their specific responses to these factors. Two sources of nitrogen, sodium nitrate and ammonium nitrate, in two concentrations were added to BM-1 medium, and seeds were plated. Additionally, seeds sampled from four populations were tested to look for intraspecific variation in germination response. Early germination results throughout all populations indicate contamination from seed or airborne sources is a persistent problem with asymbiotic germination, but the plates with ammonium nitrate seem to have far less contamination than that of the plates with sodium nitrate. This work is important because it adds to our understanding of orchid seed germination and how species respond at different life stages to a constantly changing environment.