This study is conducted to investigate the effects of growth characteristics (GC) and DPPH radical scavenging activity (DRSA) of the heading lettuce ‘Fidel’ depending on four concentrations of activated mineral groups (AMG: 1.6% active minerals and 0.03% CaO) added to basic nutrient solutions (diluted by 0, 0.05, 0.1, and 0.2%) and on four different light-emitting diodes (LED; B:R:W ratio = 0:1:12, 0:1:9, 0:5:5, and 2:3:5). Both 0.1 and 0.2% AMG showed better GC of lettuce in plant width, plant length, leaf width, leaf length, and the number of leaves than those of other AMG, while leaf thickness and chlorophyll value did not show significant difference among all AMG. Moreover, 0.1 and 0.2% AMG showed heavier shoot fresh weights than those of other AMG. As for the combinations of AMG and LED, B0:R5:W5 showed the best lettuce GC regardless of AMG compared to other AMG and LED combinations. As shown in the above results of LED, although there was a difference in lettuce growth by LED, the differences of lettuce growth by AMG were statistically significant. The DRSA was the highest at 82.8% in B2:R3:W5, followed by B0:R5:W5 at 77.8%. LED showed differences but AMG did not affect DRSA. Therefore, the optimal conditions in plant factory for GC and DRSA of the lettuce were 0.1% AMG and B0:R5:W5.

Abstract
Introduction
Materials and Methods
    Plant materials and Plant Factory
    AMG and LED
    Radical scavenging activity (DPPH assay)
    Statistical analysis
Results and Discussion
    Growth characteristics in heading lettuce by AMG concentrations added to nutrient solution
    Growth characteristics in heading lettuces by the combination of AMG and LED
    Measurement of DPPH radical scavenging activity
References

• Tae-Eui Song(Department of Horticulture Life Sciences, Hankyong National University)
• Seong-Jik Park(Department of Bioresources and Rural Systems Engineering, Hankyong National University)
• Joon-Kwan Moon(Department of Plant Life and Environment Sciences, Hankyong National University)
• In Soo Kim(Insungtec Company Limited)
• Chang Hee Lee(Department of Horticulture Life Sciences, Hankyong National University) Corresponding author