Case Study: Genetic research on the mechanism of heat generation in plants

Use of thermal cameras can lead to prompt discovery of new exothermic plants

The Kazusa DNA Research Institute was founded in 1994 as the world’s first facility specialized in DNA-related research. The institute’s mission is to widely contribute to various fields such as medicine, agriculture, industry, and education, while at the same time leading the world in DNA research activities.

Dr. Mitsuhiko Sato, a project researcher who specializes in evolutionary biology, wanted a way to observe and record temperature changes in plants that generate heat without disturbing them. He recently purchased a Teledyne FLIR T530 thermal imaging camera for his research.

The Kazusa DNA Research Institute, and Dr. Mitsuhiko Sato

Investigating temperature changes in a skunk cabbage, an exothermal plant

Some plants generate heat—about 90 different varieties worldwide. But because temperature is invisible, there might be even more heat-generating "exothermal" plants that haven’t been discovered. One of the few researchers engaged in the research of exothermal plants is Dr. Sato, a project researcher at the Kazusa DNA Research Institute.

"I am currently studying Symplocarpus foetidus var. latissimus in Araceae, which is a related species of the skunk cabbage. The plant blooms in early spring right after thawing when the external temperature is close to zero," says Dr. Sato. "However, the plant generates heat at night that reaches about 20 degrees centigrade and maintains that temperature for about one to two weeks during the flowering season. It is not a homoiothermic animal but a homoiothermic plant. In addition, there are plants like the sago palm (below) that are referred as ‘poikilothermic plants’ since they generate more heat when it is hot." For measurements of exothermal plants, Dr. Sato conventionally employed a thermocouple data logger and inserted a needle-shaped probe into the flower to trace temperature changes. However, if the probe is inserted into the flower, it can cause the plant to die. In addition, thermocouple measurements with a data logger only measures the temperature of the location where the needle is inserted. Hoping to obtain a more accurate idea of which points of the flower generate the most heat without damaging the flower, Dr. Sato decided to purchase a thermal camera. As he researched which camera to buy, his joint researcher introduced Dr. Sato to the Teledyne FLIR thermal camera.

"When purchasing new equipment, it is important that the equipment has the ability to reproduce the results in research. My joint researcher suggested to purchase the Teledyne FLIR thermal camera in order to measure the temperature of the flower without damaging it. This idea is what we emphasize when purchasing other equipment as well," he says. "I participated in a FLIR online seminar where I received an easy-to-understand explanation of how to best utilize the camera. I made my final decision based on how easy it was to use the camera and because I was able to purchase it at an academic discounted price."

Picture of a male sago palm flower. Close-up on the left and full image on the right

Making it possible to conduct observations by taking the camera to a place deep in the mountains where plants grow naturally

When observing plants, equipment usability is an important factor. "I currently conduct observations in the institute and its surrounding areas, but I want to carry equipment to places where plants grow naturally such as deep in mountains. The easiness of carrying the Teledyne FLIR thermal camera was attractive to me," Dr. Sato explains. In his research, Dr. Sato uses both a data logger to collect data of changes over time and a thermal camera to collect easy-to-understand and impactful images.

"When I was using the data logger only, I sometimes felt uncertain about the measurements taken, but with the thermal camera, I can confirm the measurements on the spot, which is a great help," he says.

Taking an outside photograph

Identifying exothermal genes and summarizing the findings in a thesis

"Exothermal plants generate heat instead of ATP (adenosine triphosphate) as energy when the mitochondria breathe. That means they have a heat-generating mechanism written in the blueprint of their genes, which is passed down unbroken from generation to generation. The Kazusa DNA Research Institute is a globally renowned institute that specializes in plant and human genomes. I will continue my research in order to reveal the mechanism of heat generation in plants at the genetic level," says Dr. Sato. Once the researchers better understand the mechanism of heat generation, they will be able to reproduce it and eventually enable non-exothermal plants to generate heat. That could lead to plants that better withstand the cold—for example, growing rice in cold regions or breeding mangos outside of tropical zones. It might be possible to expect them to contribute to food issues and agricultural applications.

"What genes are used when they generate heat? I am now preparing a thesis by utilizing the images I have taken with the thermal camera while identifying exothermal genes," says Dr. Sato. He adds, "I anticipate great benefits from the applications of a thermal camera in my research. There are huge possibilities in terms of the discovery of exothermal plants that are not yet known and the elucidation and research of new knowledge."

Professional thermal camera - FLIR T530

Learn More