Eternalizing the Endangered: The Essential Role of Micropropagation in Hawaiian Plant Conservation Talia Rubnitz Hokule ʻ a Program, Washington University in St. Louis Background Hawai ʻ i is nicknamed “the endangered species capital of the world” Although Hawaii occupies less than 1% of United States territory, it houses 40% of the nation’s endangered plant species Micropropagation is an important management option for plants with dwindling numbers Micropropagation is the cloning of plant materials to increase their population size Through the Hokule ʻ a program, I went to Hawai ʻ i for four weeks I had a research internship with the Lyon Arboretum, an educational research center, which houses the only micropropagation facility in the state At the Lyon Arboretum, I interned in the micropropagation lab Methodology Using aseptic, in vitro techniques, I operated in a sterile hood with sterile tools. At the arboretum, plant technicians use Murashige and Skoog medium as the main source of food for the cultivated plants. This gel-like material resides at the bottom of each test tube. In order to successfully micropropgate plant material, I made sure the hood, as well as the tools I used, typically a scalpel and tongs, were sterile. I then took a test tube with an overgrown, unhealthy plant, opened it in the hood, and laid it down on a sterile piece of paper towel. Next, I removed old and decaying plant mater from the specimen and cleaned off the parts of the plant that were to be replanted. Once this was done, I replanted the plant segments in a new test tube with fresh medium. The test tubes were then put in the lab’s basement with 25,000 other cultivated plants to grow in a temperature and light controlled environment where the plants thrive. Discussion At the Lyon Arboretum, micropropagation increases the population sizes of culturally, biologically, and environmentally important taxa The arboretum has successfully saved over 80 endangered species from the brink of extinction This form of plant cultivation is much more efficient and has a higher success rate than growing plants in soil By increasing the population size, micropropagation successfully brings species back from the brink of extinction The use of micropropagation in the conservation of endemic endangered species in places like Hawai ʻ i will preserve millions of years of floristic evolutionary history Results During my time in Hawai ʻ i, I successfully propagated over 300 plants Using micropropagation, I was able to drastically increase the population sizes of these species Acknowledgements I would like to acknowledge: Anu Hittle, WU Career Center and Hokule ʻ a Program Director Dr. Tiffany Knight, WU Department of Biology Nellie Sugii, Pete Wiggin, Cindy Nose, and everyone at the Lyon Arboretum who I worked with this summer WU Environmental Studies Program WU Office of Undergraduate Research WU Career Center Mint Taro Species Worked On Taro (Colocasia spp.), otherwise known as Kalo, is a culturally significant crop plant. At Lyon, around 70 varieties of taro are being cultivated in order to safeguard genetic variations and preserve crucial elements of Hawaiian culture. Phyllostegia hirsuta, an endangered species of Native Hawaiian Mint, which is cultivated to increase numbers and proliferate them. It is estimated that there are fewer than 300 members in the wild. Different Techniques: Since the two species have different growing points, I used distinctive practices on each that catered to their unique methods of growth. Taro is a monocot plant, meaning it only has a growing point associated with its stem and has no lateral or secondary growth. When propagating, the corm and smaller taro plants, each with their own corms, can be replanted. Mint is a dicot plant, thus it has secondary and lateral growth. This means you can plant parts of the plant that were not originally the plant’s place of growth. When propagating, the tops of each stalk are replanted, as well as the tops of the lateral growths. Although these are not associated with the original stem and root system, its growing mechanism enables the plants to grow from any lateral incision. Above: Micropropagation being performed on the native mint species, Phyllostegia hirsuta, in a sterile hood at the Lyon Arboretum, Honolulu, Hawai ʻ i Above: These photographs show the individual steps involved in micropropagation of both the mint (top) and taro (bottom) species. Top: Newly micropropagated Phyllostegia hirsuta plants. Bottom: The storage room for micropropagated materials