A Case Study to Conserve Trillium: Can The Seeds Survive Drying?

Posted August 18, 2016
Courtney Dvorsky working in the plant lab
Courtney Dvorsky working in the plant lab

Guest blogger: Courtney Dvorsky, CREW Plant Lab Intern

Growing up in Cincinnati, my love for conservation research grew each time I visited the Cincinnati Zoo & Botanical Garden.  As a kid, I attended summer camps, and in 2008 and 2009, I was a VolunTeen.  Now, seven years later, I had the amazing opportunity to be an Intern with the Zoo’s Center for Conservation and Research of Endangered Wildlife (CREW) plant division!  The project I worked on, funded by the Association of Zoo Horticulture (AZH), focused on determining if seed banking could be an option to help conserve some of the endangered trillium species.

White trillium (Photo: Joshua Mayer)
White trillium (Photo: Joshua Mayer)

There are many species within the Trillium genus of spring wildflowers, most of which are native to North American woodlands. With three petals, three sepals and three leaves, they are commonly called trinity flowers. Many trillium species, including the Ohio state wildflower, the white trillium (Trillium grandiflorum), still thrive in the wild. There are others, however, that are threatened or endangered such as the persistent trillium (Trillium persistens).

Trillium seeds were planted in soil boxes for germination
Trillium seeds were planted in soil boxes for germination

My first task was to set up germination trials to compare germination in soil with germination in vitro (in tissue culture) for several different trillium species.  Many trillium seeds have a double dormancy, meaning they need two cold periods to germinate entirely.  Thus, it takes about two years for a seed to germinate into a trillium seedling.  Unfortunately, as a result, I won’t see germination while I am at CREW.

My second task was to determine if the seeds could withstand drying in order to be seed banked.  Seeds that are banked must be under 20% moisture content so we began by analyzing the initial moisture in the seeds directly out of a fruit pod.  We then dried the seeds to different moisture levels using air, silica gel, and three humidity levels created in containers with three different saturated salt solutions (NaCl, MgCl, and LiCl).

Desiccators, in which trillium seeds were dried to different moisture levels in this study
Desiccators, in which trillium seeds were dried to different moisture levels in this study

After the seeds were dried, we analyzed them for moisture content and viability using a stain known as TTC (triphenyl tetrazolium chloride). If the seed is still viable, it will stain red. If the seed is not viable, it will not stain at all. So far we succeeded in drying the seeds to under the 20% moisture content needed for seed banking; however, they are often not viable. CREW is running more tests to try to repeat these results in the months to come.

Trillium seeds tested for viability with TTC. Living seeds stain red; dead seeds remain white.
Trillium seeds tested for viability with TTC. Living seeds stain red; dead seeds remain white.

Unfortunately, my time as an intern has come to an end. Luckily, I will be just a short distance away working on my PhD at Miami University of Ohio, so I will be able to check in on my seeds. Here’s hoping for some germination!