Transcript The Essential Role of Micropropagation in

Eternalizing the Endangered:
The Essential Role of Micropropagation in Hawaiian Plant Conservation
Talia Rubnitz
Hokuleʻa Program, Washington University in St. Louis
Background
• Hawaiʻi 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 Hokuleʻa program, I went to Hawaiʻi 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
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.
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 Hawaiʻi will preserve millions of years of floristic evolutionary
history
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.
Mint
Above: Micropropagation being performed on the native mint species, Phyllostegia
hirsuta, in a sterile hood at the Lyon Arboretum, Honolulu, Hawaiʻi
Taro
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.
Top: Newly micropropagated Phyllostegia hirsuta plants.
Bottom: The storage room for micropropagated materials
Acknowledgements
I would like to acknowledge:
Above: These photographs show the individual steps involved in micropropagation
of both the mint (top) and taro (bottom) species.
Results
•During my time in Hawaiʻi, I successfully propagated over 300 plants
•Using micropropagation, I was able to drastically increase the population sizes of
these species
•Anu Hittle, WU Career Center and Hokuleʻa 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