Effects of Ultraviolet-B Radiation on the Regulation of Ascorbic Acid Accumulation and Metabolism in Lettuce

Abstract

To understand the effect of ultraviolet (UV)-B irradiation on the antioxidant capacity and growth of lettuce (Lactuca sativa), we subjected lettuce plants to UV-B irradiation (15.55 kJ m−2 d−1) for 7 days and measured yield, photosynthetic performance, hydrogen peroxide (H2O2), reduced glutathione (GSH), and ascorbic acid (AsA) contents, and the enzyme activity and expression of genes involving AsA recycling. UV-B exposure did not significantly decrease the fresh/dry weight of the lettuce shoots. The net photosynthesis rate, internal CO2 concentration, transpiration rate, and stomatal conductance decreased during the first 4 days of irradiation and light but recovered at day 7. In UV-B-treated plants, the levels of AsA, GSH, and H2O2 increased significantly and simultaneously, with a positive correlation found between H2O2 and AsA or GSH levels. UV-B exposure upregulated the expression level of most genes encoding the enzymes involving AsA recycling but downregulated the associated enzymatic activities. The increase of AsA content in UV-B-exposed lettuce might contribute to the AsA–GSH cycle, leading to downregulation of ascorbate oxidase (AO) enzymatic activity and gene expression. UV-B irradiation had a greater impact on metabolite levels than time of UV-B treatment. These results suggest that AsA homeostasis in UV-B-treated lettuce is regulated through a feedback loop between the expression and activity of enzymes associated with AsA recycling. Short-term UV-B supplementation (24 h) could be a promising approach to enhance AsA content in lettuce.

Key Materials in Solder Mask Ink for Printed Circuit Board

“…All these characteristics contributed to the preparation of PCB which used for the 5 th generation mobile communication system. [73] Chopra et al adopted amide gellants to improve the performances such as scratch resistance and adhesion of the acrylic acid resin SMI layer. The invented SMI made of acrylate monomers, oligomers, and other necessities can be used to fabricate high-resolution PCB by inkjet printing.…”

Light spectrum affects growth, metabolite profile, and resistance against fungal phytopathogens of Solanum lycopersicum L. seedlings

“…Light has been shown to influence the susceptibility of vegetable plants to various bacterial (Leuconostoc mesenteroides) and fungal (Botrytis cinerea, Fusarium graminearum and Penicillium digitatum) pathogens (De Lucca et al 2012;Rasiukevičiūtė et al 2021). For instance, UVB radiation can induce the production of flavonoids and phenolic compounds in lettuce, which have antimicrobial properties (Liu et al 2023). Furthermore, light quality and intensity can affect the expression of defense genes, such as those encoding pathogenesisrelated proteins and enzymes participating in the synthesis of phytoalexins (Esco barBravo et al 2019).…”