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Research team studies the evolution of biodiversity in the tropics

Experience told Assistant Professor Grace F. Chen, Ph.D., that her window to hand pick 1,600 seeds from two tropical plant species in the jungles of Panama was short. Too many unpredictable variables could spell the difference between success and failure for her collaborative scientific research project.

After all, the Misericordia University biology professor had to trek more than 2,290 miles from campus to Pipeline Road, about 20 miles north of Panama City, to access the rainforest in Soberania National Park and travel muddy, obstacle-ridden terrain to find her targets, Costus allenii and Costus villosissimus, in the right stage of their life cycles.

Costus allenii and Costus villosissimus are closely related plant species, commonly found in remote tropical rain forests in Colombia, Costa Rica, Panama and Venezuela. Dr. Chen can only harvest viable seeds from mature fruits that typically ripen in mid-October, but can vary from late September to early November. “The only time I could go was during fall recess (Oct. 16-19),͛͛ she says about her expedition in 2016. “I did not have the luxury to stay in the area and wait for the fruits to mature.

This was one of the biggest risks, as I was afraid I might not be able to collect any seeds for the experiment.͛͛In this case, Dr. Chen had three days to complete her mission and acquire the main ingredient required for the 2016-17 Faculty Research Grant, Effects of Periodic Water Availability on Delayed Seed Germination in Neotropical Costus Species. Early arrival meant the fruits were not mature, and coming too late may correspond to fruits being removed by animals or falling on the forest floor.

“Costus allenii and C. villosissimus are so interesting. They are closely related to each other with many similar characteristics,͛͛ Dr. Chen says, explaining her fascination with these plants. “They are close enough that they can produce viable, fertile hybrids in the greenhouse. Yet, we can clearly distinguish the species from one another. There is no doubt that they are two distinct species in nature. That is what interests me: They are so similar, yet so different.͛͛Collaborating with the Smithsonian Tropical Research Institute in Panama and a Panamanian undergraduate assistant, Dr. Chen collected seeds from plants deep inside the rainforest and from the edge of the jungle off Pipeline Road, an 11-mile historic access road built during World War II that dissects the rainforest.

The rainy season, though, wreaked havoc on their route. Armed with a nearly decade-old map, experience and some good fortune, Dr. Chen set out in a specially equipped Toyota Hilux pick-up truck to re-explore the same jungle she grew familiar with while working on her doctorate dissertation from 2004-10. The familiarity with the roadway and region proved beneficial when extremely muddy conditions forced them to continue by foot. “If I did not have the knowledge of when and where the adult plants were going to set the fruits and seeds, I would not be able to do this at all,͛͛ Dr. Chen says about the importance of her prior experiences in Panama. “We realized it was probably not a good idea to keep driving, so we parked the truck aside and took off on foot,͛͛ she recalls. “It turned out a tree fall blocked the road not too far from where we parked.

That is where the luck comes in: as we walked a couple kilometers forward, we found the samples we needed.͛͛On campus, Misericordia University student researchers Jasmine Morningstar ͛19, Nanticoke, Pa.; David Kunkel ͚19, Tamaqua, Pa., and Katie Tota ͛18, ͛21, Clinton, N.J., participated in the census of the seed germination progress twice a week for the first seven months and once a week thereafter, monitoring the seeds in the controlled environment of the growth chamber in Hafey-McCormick Science Hall. “It really helped me see what the field of research entails,͛͛ says Kunkel, who learned about plant adaptation, general research methods and much more as a research assistant. “Originally, I wanted to pursue an advanced degree in microbiology, but this research helped me realize that I enjoy evolutionary ecology more.

“Undergraduate research is very important because most graduate schools are looking for more research experience in conjunction with the courses I took,͛͛ adds Kunkel, who plans to attend graduate school for plant evolution. The ongoing study enhances scientists͛ understanding of how local adaptation contributes to speciation – the process of one species diverging into two – leading to the high biodiversity in the tropics. It also will be the foundation for more ecological and evolutionary research in the future, according to Dr. Chen. As they try to determine how plant species respond to rapid changes in the environment, their targeted work may have a broader implication regarding the Earth͛s ever-changing climate.

Dr. Chen͛s previous studies suggested that the seeds of C. allenii germinated right after sowing, while those of C. villosissimus germinated at the beginning of the rainy season, about five months after sowing. “As our climate becomes rather unpredictable, will unexpected precipitation during the dry season induce seed germination of Costus villosissimus,͛͛ she asks hypothetically? “Can we trick plants to germinate earlier?͛͛ In Misericordia͛s 16-month and ongoing case study, the research team controls environmental conditions, including temperature, light, and day length, but varies the availability of water through simulated drought with different durations. After seven months of intense census, the team is still monitoring the seeds weekly and recording their germination status today. The preliminary results suggest that it is possible to induce the early seed germination of C. villosissimus.

“It really taught me a lot about what is involved with research,͛͛ says Tota, an undergraduate biology major who is planning to pursue her doctorate in physical therapy. “It is not just a research paper. There are months, years that go into research, so be patient when working on things because science is an ongoing process.”