Elicitation and Enhancement of Phenolics Synthesis with Zinc Oxide Nanoparticles and LED Light in Lilium candidum L. Cultures In Vitro

Abstract

In this study, we identified and determined the content of phenolic compounds in Lilium candidum adventitious bulbs formed in vitro. HPLC analysis revealed the presence of four phenolic acids: chlorogenic, caffeic, p-coumaric, and ferulic acid. Phenolic acid content was assessed in adventitious bulbs formed in vitro on media supplemented with zinc oxide nanoparticles (ZnO NPs at 25, 50, and 75 mg/L) under fluorescent light (FL) or in darkness (D). The second experiment analyzed the effects of light-emitting diodes (LEDs) of variable light spectra on the formation of adventitious bulbs and their contents of phenolic acids. Spectral compositions of red (R; 100%), blue (B; 100%), red and blue (RB; 70% and 30%, respectively), a mix of RB and green (RBG) in equal proportions (50%), and white light (WLED, 33.3% warm, neutral, and cool light, proportionately) were used in the study. FL and D conditions were used as controls for light spectra. Bulbs grown in soil served as control samples. The most abundant phenolic acid was p-coumaric acid. Treatment with LED light spectra, i.e., RB, RBG, WLED, and B, translated into the highest p-coumaric acid concentration as compared with other treatments. Moreover, all the bulbs formed in light, including those grown on the media supplemented with ZnO NPs and under FL light, contained more p-coumaric acid than the bulbscales of the control bulbs grown in soil. On the other hand, control bulbs grown in soil accumulated about two to three times higher amounts of chlorogenic acid than those formed in vitro. We also found that the levels of all examined phenolics decreased under FL, R, and D conditions, while the bulblets formed in vitro under RB light showed the highest phenolic content. The use of ZnO NPs increased the content of p-coumaric, chlorogenic, and caffeic acid in the bulblets formed under FL as compared with those grown in darkness.

The Effect of Combined Elicitation with Light and Temperature on the Chlorogenic Acid Content, Total Phenolic Content and Antioxidant Activity of Berula erecta in Tissue Culture

“…Further studies should investigate the influence of such elicitors on the biosynthesis of chlorogenic acid in Berula erecta . Elicitation with exposure to a mix of red and blue light [ 55 ], methyl jasmonate [ 56 , 57 ], salicylic acid [ 57 ], methyl salicylate [ 58 ], titanium (IV) ascorbates [ 58 ], zinc oxide nanoparticles [ 55 ] and the fungal elicitor Phytophthora megasperma [ 59 ] should be investigated in the future. It has also been reported that the production of secondary metabolites in plants can be stimulated by exposure to heavy metals [ 60 ].…”

“…In such a study, it would be necessary to test the effects of individual elicitors instead of combined elicitation, which would provide a better insight into the physiological response of Berula erecta to individual elicitors. Also, other types of elicitation should be tested in the future [ 55 , 56 , 57 , 58 , 59 , 60 ], and the extraction process of chlorogenic acid from plant material should be optimised [ 104 ]. However, obtaining secondary metabolites using the technique of in vitro plant cultures also has disadvantages, such as low biomass yield, higher production costs, the maintenance of a controlled environment, the need for specialised manpower, a small number of profitable large-scale plants and the high cost and complexity of extraction, purification and analysis of the produced metabolites [ 105 ].…”

Analysis of architecture of chrysanthemum plantlets in response to zinc oxide, silver and auxin treatment in shoot-tip culture

“…ese suggest that zinc nanoparticles may be used as a substitute for exogenous auxins in plant in vitro cultures. Moreover, Zn is an essential plant micronutrient playing an important role in plant growth, propagation, and yielding by controlling the activity of enzymes and hormones in many integral metabolic processes, as well as regulating the biosynthesis of chlorophyll, proteins, carbohydrates, phenolics, DNA, and RNA (Awan et al, 2021;Pałka et al, 2023).…”