Abstract
Dream Lake, Yangmingshan is the unique natural habitat of Taiwan isoetes (Isoetes taiwanensis). In recent years, this species were in the risk of wild extinction because of losing capacity of lake water and terrestrialisation. The long-term germplasm preservation is urgent work for conservation. In this study, we will evaluate how to obtain effective spore and culture young plants. Results showed that the sporangia of Taiwan isoetes were white, flat, thin shaped in January, and then the volume of sporangia gradually increase in Feburary-May, sporangia were light brown. Sporangia were brown and dark brown in June and July-October, respectively. Mature sporophylls began to detach mother plant, floated on the surface of lake and released spores in November – December. It was suggested that the suitable reason was early spring to collect most abundant fresh spores. In addition, were collected soil samples from six points and 5 kinds of depth of soil within each point in Dream Lake. They were taken back to the labotary for the cultivation of soil spores. Young plants did not produce after 20 days culture, and did no longer increase the young plants after 80 days culture. The amount of young plants was associated with the points and soil depth. Usually, more young plants were produced from soil, which sampled closer to the center and upper sites (0-20cm) of the lake. Therefore, the soil spores using for conservation, should sample soil from center and upper sites in the late winter (January-February). It can produce more Taiwan isoetes young plants.