Effect of Light Treatment and Maturity Stage on Biomass Production and Bioactive Compounds of Two Pepper Cultivars under a Deep Water Culture Hydroponic System

Abstract

Previous pepper studies indicated that biomass production and the amounts of bioactive compounds were dependent on light sources, maturity processes and pepper genotypes. However, the above topic has received little attention in supplemental light versus cultivar combinations under a hydroponic growing system. Therefore, the aim of this study was to evaluate the biomass production (fruit, root, stem and leaf) and fruit bioactive compounds (vitamin C, total flavonoid content and antioxidant capacity-AC-FRAP, total polyphenol-TPC) of two pepper cultivars (‘Fehérözön’-Fö and ‘Szegedi 80’-S80) in three fruit maturity stages (green, beaker and red) under two LED light treatments (full-F and blue-white-BW spectrums) in a deep water culture hydroponic system. The stem biomass and water use for total and fruit biomass were significantly different for cultivars and light treatments. Light treatments, maturity stages and cultivars had significant effects on fruit biomass production and on all bioactive compounds. However, the results on the bioactive compounds varied according to the green, beaker and red maturity stages of the two pepper cultivars. In correlation analyses, 30 pair-variables correlated significantly and nine showed values r > 0.9 for fruit weight versus (vs.) vitamin C, fruit weight vs. AC-FRAP, fruit weight vs. TPC, vitamin C vs. AC-FRAP, vitamin C vs. TPC, AC-FRAP vs. TPC, and flavonoid vs. TPC. This study suggested that additional lights and maturity features of cultivar genotype strongly determined the biomass and bioactive compounds of pepper under a deep water culture hydroponic system.

The Effect of the Daily Light Integral and Spectrum on Mesembryanthemum crystallinum L. in an Indoor Plant Production Environment

“…The results for TAC and vitamin C at 21 h DLI suggest that light receipt 1 (Table 3), with the high proportion of blue and green light spectra, tended to yield higher TAC and vitamin C contents when compared to the other light treatments. It was reported in [29] that when plants experience various stresses, the antioxidant content increases because of the accumulation of secondary metabolites. Blue light has a shorter wavelength and thus possesses more energy than red light, and therefore can be considered as a stress factor, resulting in higher phytochemical contents of antioxidants, and vitamin C especially.…”