University of Cincinnati biology faculty Susan Dunford and Valerie Pence and former biology graduate student Bernadette Plair recently returned from an expedition to the rainforests of Costa Rica where they experimented with new techniques to collect and preserve tropical plants.
Pence and Plair have been working for the last several years to develop more effective techniques to collect endangered plants. Their previous field sites have been in Plair's homeland of Trinidad, and much of the laboratory work is done at the Cincinnati Zoo and Botanical Garden's Center for Research of Endangered Wildlife (CREW). Pence is head of the Plant Conservation Division at CREW and an adjunct faculty member at UC. Plair is now a researcher at CREW.
This spring, they tried out their methods at the La Selva preserve in Costa Rica run by the Organization of Tropical Studies. The techniques are designed to be fast, simple, and not harmful to the living plants. So, they use a basic hole-puncher to retrieve tiny samples of cells and tissues from plants which are then carted back to the lab in tiny vials of culture medium to be grown into whole new plants.
Dunford joined the group to look specifically at how to protect plant tissues during the dehydration, freezing, and rehydration that is used in the collection and preservation of some plant tissues.
"A lot of the damage is done on rehydration," explained Dunford. "The cell membranes get disrupted as it dries, and you can find the holes when you rehydrate."
Fortunately, most plants know how to protect themselves naturally during dry times. They secrete a hormone called abscisic acid or ABA. ABA triggers a chain of events, including the accumulation of sugars and proteins which proetect the cell membranes during drying.
If the UC and CREW biologists can find a way to utilize and enhance the plant's natural defenses against drying, it should improve the surviability of the plant samples they collect.
Dunford, who normally conducts plant physiology experiments in the laboratory, said she was awed by the beauty of the tropical reainforest and a bit intimidated by the non-plant wildlife. "The trees were amazing. I saw agoutis and lots of birds, but they have venomous snakes and other critters. I wish I had taken a bigger flashlight," she joked.
Luckily, the snakes stayed out of the researchers' way, and they were able to finish their field work on time despite heavy rains during most of their visit. They should know sometime this summer how many of their plant samples survived.
All of the experimental work was done on plant species which are not endangered. Thirty species were collected in all, ranging from tiny bryophytes to the flowering Piper plant. The research was funded by the Cincinnati Zoo and Botanical Garden and with private funding from Professor Dunford.