Category — plant research
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.
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).
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).
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.
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!
August 18, 2016 5 Comments
Guest blogger: Christina Del Greco, CREW Plant Lab Intern
Hi! My name is Christina Del Greco. I’m a college sophomore studying biology at the University of Notre Dame. Thanks to a grant from the Association of Zoological Horticulture (AZH), I had the wonderful opportunity to be a plant lab intern with the Zoo’s Center for Conservation and Research of Endangered Wildlife (CREW) this summer.
As a CREW intern, I worked on the oak tree conservation project. Scientists store seeds in seed banks for many plants, especially endangered ones, as a precaution in case the wild population of a plant gets too low. However, you can’t do that for oak trees, as the acorns don’t stay viable if they are frozen. This means that there has to be another way to build up a bank of oak tissue. CREW has been pursuing oak stem tip culturing, in which the tips of oak seedlings are put into test tubes filled with media meant to help the plants grow. This way, we can store test tubes of seedlings instead of acorns.
The problem is there are so many different types of media with different concentrations of various nutrients the plants need, and each species grows differently than the others. My main project was to work on a Design of Experiments (DOE—a statistical method of setting up experiments) project in which 26 different types of media are used for four different oak species to compare growth on different media and gather data in order to compare them.
I took pictures of each of the plants after one month in culture, and then again after two months in culture. I also kept track of things such as whether the plants were infected by bacteria or fungus, how tall they grew, if the medium they were in turned brown, if any leaves were growing, and more. All of these variables are able to potentially tell us something about what makes the oaks grow better or worse.
The data is sent to a collaborator at the United States Department of Agriculture (USDA) who knows far more about statistics than I do, and he can use the results to determine if any of the particular nutrients had a noticeable effect on the growth of the oaks. In the future, once all of the statistical results come back, we can use that data to create what we hope to be the optimal medium on which an oak shoot can grow.
I worked on a few smaller side projects as well. One was to try and determine at what point you should trim off the tip of an oak seedling to put it in the medium. Generally, we clip off the stem tips relatively early in the plant’s development, but there has never been any consistency, so I chose three relative stages in three different species and put them in culture to see which one grew best.
I also started a few petri dishes to try to initiate somatic embryogenesis, which is a process in which we try to force plants to make embryos by placing non-embryonic parts of the plant (somatic tissue), such as small leaves, on a special medium in the dark to try and force an embryo to form on its own.
And, when an incredibly old red oak tree fell in the middle of the Zoo, I had the opportunity to collect samples to see if there was any way we could regrow the tree in the future, allowing me the opportunity to use all of the methods I had learned about at once.
I learned so much over this internship. Besides learning all sorts of new lab techniques, I had no idea there were so many different ways to try and conserve different species of plants. I also didn’t know that there are so many different endangered oak trees. I am incredibly grateful for the opportunity I had to work at CREW for the summer and learn all about conservation efforts both here and at zoos and botanical gardens all over the world.
August 16, 2016 2 Comments
The Plant Division at CREW is now using time-lapse photography to capture the growth of plants in vitro. Using a digital SLR camera, we program the camera to take a photograph of the plants every 30 minutes.
In general, it takes about two months before the test tube plants need to be subcultured onto fresh media. Now we can condense weeks of growth images into a 1-minute video. Watch the awned meadowbeauty (Rhexia aristosa), a flowering perennial from the Eastern United States,grow!
We initially observed the plants responding to the daily 16-hour light/8-hour dark cycle in the growth chamber. The leaves of the plants appear to “pulse” upward as the light automatically turns on each morning. The “sleep movements” of plants are well documented in terrestrial settings, but until now we had not observed them in plants grown in vitro at CREW. Time-lapse photography has also been a useful tool in comparing different types of media. We photograph a single species on different media to detect changes in growth patterns depending on the medium.
To date we have completed time-lapse videos of three species. The goal is to create a video for every species in the growth chamber. Since a single sequence can take up to six weeks to complete, we have our work cut out for us to create videos for the 35 to 50 species in the growth chamber!
(Reprinted from the Fall 2015 CREW Review)
March 2, 2016 No Comments