Effect of mixed light emitting diode spectrum on antioxidants content and antioxidant activity of red lettuce grown in a closed soilless system

Sopanat Sawatdee; Teeraya Jarunglumlert; Prasert Pavasant; Yasuko Sakihama; Adrian E Flood; Chattip Prommuak

doi:10.1186/s12870-023-04364-y

Effect of mixed light emitting diode spectrum on antioxidants content and antioxidant activity of red lettuce grown in a closed soilless system

BMC Plant Biol. 2023 Jul 6;23(1):351. doi: 10.1186/s12870-023-04364-y.

Authors

Sopanat Sawatdee¹, Teeraya Jarunglumlert², Prasert Pavasant³, Yasuko Sakihama⁴, Adrian E Flood⁵, Chattip Prommuak⁶

Affiliations

¹ School of Energy Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wang Chan, Rayong, 21210, Thailand.
² Faculty of Science, Energy and Environment, King Mongkut's University of Technology North Bangkok (Rayong Campus), Ban Khai, Rayong, 21180, Thailand.
³ Tree Moments Co. Ltd, Bangrak, Bangkok, 10500, Thailand.
⁴ Graduate School/Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan.
⁵ School of Energy Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wang Chan, Rayong, 21210, Thailand. adrian.flood@vistec.ac.th.
⁶ Energy Research Institute, Chulalongkorn University, Pathumwan, Bangkok, 10330, Thailand. chattip.p@chula.ac.th.

Abstract

Background: Light spectra have been demonstrated to result in different levels of comfort or stress, which affect plant growth and the availability of health-promoting compounds in ways that sometimes contradict one another. To determine the optimal light conditions, it is necessary to weigh the vegetable's mass against the amount of nutrients it contains, as vegetables tend to grow poorly in environments where nutrient synthesis is optimal. This study investigates the effects of varying light conditions on the growth of red lettuce and its occurring nutrients in terms of productivities, which were determined by multiplying the total weight of the harvested vegetables by their nutrient content, particularly phenolics. Three different light-emitting diode (LED) spectral mixes, including blue, green, and red, which were all supplemented by white, denoted as BW, GW, and RW, respectively, as well as the standard white as the control, were equipped in grow tents with soilless cultivation systems for such purposes.

Results: Results demonstrated that the biomass and fiber content did not differ substantially across treatments. This could be due to the use of a modest amount of broad-spectrum white LEDs, which could help retain the lettuce's core qualities. However, the concentrations of total phenolics and antioxidant capacity in lettuce grown with the BW treatment were the highest (1.3 and 1.4-fold higher than those obtained from the control, respectively), with chlorogenic acid accumulation (8.4 ± 1.5 mg g^{- 1} DW) being particularly notable. Meanwhile, the study observed a high glutathione reductase (GR) activity in the plant achieved from the RW treatment, which in this study was deemed the poorest treatment in terms of phenolics accumulation.

Conclusion: In this study, the BW treatment provided the most efficient mixed light spectrum to stimulate phenolics productivity in red lettuce without a significant detrimental effect on other key properties.

Keywords: Antioxidant enzymes; Continuous light; Hydroponic cultivation; Light spectrum; Molecular antioxidants; Phenolics productivity.

MeSH terms

Antioxidants* / metabolism
Lactuca* / metabolism
Light
Photosynthesis
Vegetables / metabolism

Substances

Antioxidants