Have you ever taken a nighttime stroll around campus and noticed bright pink light emanating from the greenhouses along Curtin Road?

These luminescent laboratories aren’t something out of a science fiction novel — they’re glowing examples of plant science research being conducted in the heart of campus. Living across the street from Huck Life Sciences, I began noticing this pink light shining over the Thomas Building the day I moved in.

For months I wondered where the light was coming from. Could it be an EDM rave? A professor’s colorful office? Aliens performing tests on students?

To solve this mystery, I took a tour of one of these greenhouses with Dr. Mark Guiltinan, its lead researcher.

Although it’s crammed into tight quarters on Huck Life Sciences’ fourth floor, Guiltinan’s plant growth facility is densely packed with years of research. Each room is filled with plant specimens and tissue culture chambers, which are critical to plant research.

Known as the “lab rat” of the plant world, the Arabidopsis plant is widely used as a model organism in plant biology. Guiltinan’s lab features many samples of this genus, which are used to advance research in common crops like wheat and soybeans.

Guiltinan’s lab mainly focuses on the Theobroma cacao, commonly known as the chocolate tree. Specimens are housed in climate-controlled chambers, which mimic the warm temperature and high humidity of the habitats where they’re commonly found — places like Mexico, South America, and even the Amazon rainforest.

The Theobroma cacao plants are used to study plant genomes, disease resistance, and even the flavor and color of cocoa beans and butter. They’re just down the hall from Guiltinan’s office, so the chamber’s proximity allows him and his team easy access for their research. Products from these plants are also occasionally shipped across campus to be used in food products.

Most plants in these greenhouses utilize the pink LED lights that can be seen from the outside. These light fixtures use specific frequencies to promote plant growth and use less heat and energy than white light.

Another reason these pink lights are important to these greenhouses? Guiltinan’s lab likely wouldn’t exist without them.

“Part of the reason we put [the greenhouse] on the roof is so people would see it,” Guiltinan said. “Part of how I sold this idea [to the university] was that people would see [the greenhouse] and know about plant science at Penn State.”