Hormesis effects of gamma radiation on growth of quinoa (Chenopodium quinoa)

Abstract

Purpose

Quinoa is an annual plant that grows well in high altitude regions with high radiation and ultraviolet intensity. It has known that high-dose radiation damages living organisms, but low-dose radiation also has a beneficial effect. Therefore, the purpose of this study is to investigate the hormesis effect of gamma-ray on quinoa by growth analysis and hyperspectral imaging.

Materials and methods

Quinoa seeds were irradiated at 50, 100, and 200 Gy emitted by ⁶⁰CO. Subsequently, the seeds were germinated and transplanted into pots, then conducted growth analysis and physiological evaluation every week, and hyperspectral imaging. Photosynthetic ability was measured at 35 days after transplanting (DAT), and the plants for each dose were divided into aerial and underground parts for biomass evaluation at 91 DAT. Various vegetation indices were estimated from 14 to 35 DAT by hyperspectral analysis, and the specific bands were extracted based on the PLS model using plant height, SPAD value, and chlorophyll fluorescence parameters.

Results

We found that plant height and biomass were increased in quinoa plants treated with a low dose (50 Gy) as compared to control. Chlorophyll content and chlorophyll fluorescence were not different between doses at the early growth stage, but as growth progressed, the plant irradiated at 200 Gy began to be lower. The photosynthetic ability of the quinoa plant treated at 50 Gy was greater than other plants at 35 DAT. The vegetation indices related to the pigment status also were higher in the plants treated by irradiation at 50 Gy than the plants grown in other doses treatment units at the beginning of the growth. Using the PLS model we collected sensitive band wavelengths from hyperspectral image analysis. Among the collected bands, eight bands closely related to plant height, nine bands to chlorophyll content, and ten bands to chlorophyll fluorescence were identified.

Conclusion

Our results showed that the growth and physiological parameters of quinoa treated by low dose gamma irradiation to seeds were greater than that of control as well as the plant with higher doses. These findings confirm that the positive changes in the characteristics of quinoa with low dose radiation indicated that hormesis occurs at 50 Gy radiation.

Keywords:

• Hormesis
• gamma radiation
• quinoa
• hyperspectral imaging
• Chenopodium quinoa

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was supported by the Korean Ministry of Environment [grant no. 2018002270002].

Notes on contributors

Ki Eun Song

Ki Eun Song is a Ph.D. candidate at Division of Applied Life Science (BK21 plus) at Gyeongsang National University and is working on plant physiology, cellar response to environmental stress including radiation.

Seung Ha Lee

Seung Ha Lee is a M.Sc. researcher in Department of Agronomy, Gyeongsang National University and is working on crop improvement and efficient management.

Jae Gyeong Jung

Jae Gyeong Jung is M.Sc. student, Department of Agronomy, Gyeongsang National University and is working on plant analysis and HIS handling in field.

Jae Eun Choi

Jae Eun Choi is M.Sc. student, Department of Agronomy, Gyeongsang National University and is working on plant management and analysis in field.

Woojin Jun

Woojin Jun, Ph.D., is a Professor of Division of Food and Nutrition, Chonnam National University, Korea and is currently working on antioxidative system in biological system.

Jin-Woong Chung

Jin-Woong Chung, Ph.D., is a Professor of Department of Biology, Dong-A University, Korea and is currently working on abnormality in cellular differentiation and development.

Sun Hee Hong

Sun Hee Hong, Ph.D., is an Assistant Professor, Department of Plant Life Science, Hankyong National University, Korea and is currently conducting a research work on plant vegetation responses to environmental stimuli.

Sangin Shim

Sangin Shim, Ph.D., is Professor, Department of Agronomy, Gyeongsang National University, Korea and is currently working on plant response to environmental stress and ecophysiological approach to changing environment.