Cold Plasma-Treated Seeds Show Potential to Protect Plants, Reduce Pesticide Use

FOURTH STATE OF MATTER — Cold plasma is applied to rice seeds to investigate its effects on plant growth and defense against the fall armyworm. (Image courtesy of Rupesh Kariyat)

MEDIA CONTACT

Maddie Johnson

U of A System Division of Agriculture
501-259-3247  |  mej048@uark.edu

FAYETTEVILLE, Ark. — The same substance that paints the sky with the Northern Lights also appears to enhance plant growth and insect defense, according to a new study.

Food science and entomology researchers from the Arkansas Agricultural Experiment Station teamed up to harness plasma and measure its effects on rice seed. The project began after Mahfuzur Rahman, assistant professor of food science, acquired a machine that produces cold plasma.

Known as the fourth state of matter, plasma is an electrically charged gas that has fluid-like behavior. Rahman points to the Northern Lights as the most familiar example of cold plasma, which means it is considered low temperature compared to the much higher temperatures of plasma in stars. Other examples of cold plasma like that generated in Rahman’s lab include fluorescent lights and neon signs.

Rupesh Kariyat, associate professor of crop entomology, became interested in investigating cold plasma’s effects from an insect perspective — an area he said had not been studied adequately.

“I thought it would be a good idea that we expose our seeds to cold plasma and then grow those seeds out into plants and ask the question of whether the plants are doing better,” Kariyat said.

“If this works, then we can come up with a method to expand at a scale where we can add cold plasma to complement existing seed treatments to boost their growth and defense against insect herbivores,” Kariyat said, noting the potential to reduce insecticide use.

One of Kariyat’s graduate students, Deepak Dilip, led the project in collaboration with Nikitha Modupalli, a postdoctoral fellow in food science and member of Rahman’s lab. Their study, “Atmospheric cold plasma alters plant traits and negatively affects the growth and development of fall armyworm in rice,” was published in Nature’s Scientific Reports in January.

Dilip served as the lead author, with Modupalli, Rahman and Kariyat serving as co-authors. Both Rahman and Kariyat are researchers with the Arkansas Agricultural Experiment Station, the research arm of the University of Arkansas System Division of Agriculture.

Tracking seed germination and plant growth

The study specifically investigated rice plant defense against fall armyworm. Seeds were treated with cold plasma and then irrigated with cold plasma-activated water, which is water that has been treated with cold plasma and has some antimicrobial properties. The plasma interacts with water molecules to generate highly reactive molecules containing oxygen and nitrogen, which effectively kill bacteria.

MEASURING GROWTH AND DEFENSE — Deepak Dilip, a graduate research assistant pursuing a master’s degree in entomology, led the experiments with strong support from Nikitha Modupalli, food science postdoctoral fellow. (Image courtesy of Rupesh Kariyat)

The results revealed that rice seeds treated with cold plasma could negatively impact fall armyworms’ growth and development.

Researchers also observed signs of improved plant growth such as more leaf growth. They also saw a faster germination rate in cold plasma-treated plants, though this was not statistically significant. It has been found that cold plasma can increase germination by eroding a seed’s surface.

Additionally, though germination rates were quicker, control plants eventually caught up with treated ones in terms of growth, making final germination counts similar between untreated and cold plasma-treated seeds. Researchers point out that this suggests cold plasma applications, though they can benefit initial plant growth, would not be as beneficial in later stages of the plant’s growth cycle.

As for the study’s impacts on the future, Kariyat and Rahman hope to apply cold plasma to the field of organic food production.

Rahman explained that the U.S. Department of Agriculture is evaluating cold plasma as an organic technology, potentially paving the way to alternatives for pesticides.

“In the future, if we can optimize this technology for organic production, it will create a very new avenue for organic food growth,” Rahman said.

​To learn more about the Division of Agriculture research, visit the Arkansas Agricultural Experiment Station website. Follow us on 𝕏 at @ArkAgResearch, subscribe to the Food, Farms and Forests podcast and sign up for our monthly newsletter, the Arkansas Agricultural Research Report. To learn more about the Division of Agriculture, visit uada.edu. Follow us on 𝕏 at @AgInArk. To learn about extension programs in Arkansas, contact your local Cooperative Extension Service agent or visit uaex.uada.edu.

About the Division of Agriculture

The University of Arkansas System Division of Agriculture’s mission is to strengthen agriculture, communities, and families by connecting trusted research to the adoption of best practices. Through the Agricultural Experiment Station and the Cooperative Extension Service, the Division of Agriculture conducts research and extension work within the nation’s historic land grant education system.

The Division of Agriculture is one of 20 entities within the University of Arkansas System. It has offices in all 75 counties in Arkansas and faculty on three campuses.

The University of Arkansas System Division of Agriculture offers all its Extension and Research programs to all eligible persons without regard to race, color, sex, gender identity, sexual orientation, national origin, religion, age, disability, marital or veteran status, genetic information, or any other legally protected status, and is an Affirmative Action/Equal Opportunity Employer.