Dr. Anirudha Dixit

Dr. Anirudha Dixit, a participant in the NASA Oak Ridge Institute for Science Education Program participant, uses Arabidopsis to model plant growth in environments similar to that of the International Space Station. This environment exhibits high levels of carbon dioxide, and the effects of this heightened CO2 on plant growth is not well characterized. He hopes that, through his research, long-term, manned space missions will become more viable.

As the technology associated with space-based science advances, manned missions to farther locations in our solar system become possible. Unfortunately, these missions are not yet realized. For long-term, manned space missions to be viable, crews who pilot and operate spacecraft require access to food for the entire duration of the mission.

While growing food in the spacecraft during these missions has shown promise, the interior environment of these vehicles poses unique challenges to plant growth. Apart from the obvious limitations in physical space aboard a spacecraft, the extreme highs in carbon dioxide (CO2) concentrations are prohibitive. At NASA’s Kennedy Space Center, Anirudha Dixit analyzes the effects of CO2 on overall plant development in an effort to make space-grown crops a reality.

CO2-rich environments like those near volcanoes and in tightly closed space stations can reach 20 times the earth’s ambient levels of the gas. At these high levels, the effects on plant life is undetermined. These levels could either be toxic or optimal for plant growth. While it is understood that these elevated CO2 levels induce a physiological response, the molecules and metabolic pathways involved are not well characterized.

“Historically CO2 levels at the ISS (International Space Station) have been between 4000 and 6000 parts per million (ppm), which is almost 15 times more than Earth’s ambient level. If plants need to be grown in such environments for food and oxygen supply, the effects of these very high levels of CO2 on plant development and physiology has to thoroughly understood,” Dixit explained.

To understand these effects on plant growth, Dixit studies Arabidopsis, a model organism for genetic research. It is small, grows quickly, and because it has been the subject of many studies, is well characterized. These traits make it similar to plants ideal for space missions.

An average day for Dixit includes checking the chambers used to replicate spacecraft environments. These chambers contain Arabidopsis and are free from many of the environmental stressors the average plant is exposed to on earth like inclement weather or insects. Following the growth of the Arabidopsis, Dixit uses genetic sequencing techniques to analyze the differences in genes that are expressed when exposed to varying levels CO2.

“In my case, I have been fortunate enough to collaborate and work with researchers in the areas of horticulture, controlled environment systems, microbiology, material chemistry, hardware development for ISS and many more. So, from a career development point of view it has been very enriching for me,” Dixit said.

In utilizing all the opportunities that the NASA ORISE Research Participation Program allows, Dixit hopes to not only enrich the capacity of manned space missions, but to also advance the quality of life on Earth.

When elaborating on this Dixit said, “It makes sense to me now, as the climate change is no longer a myth, and it could very well have a strong impact on the overall productivity of plants and global food production. My current research not only tries to understand how plants deal with very high levels of CO2 in spacecraft environments but it is also trying to understand how plants are going to respond to changing climate and CO2 levels here on Earth.”