title: LED lighting and seasonality effects antioxidant properties of baby leaf lettuce.
abstract: We report on the application of supplementary light-emitting diode (LED) lighting within a greenhouse for cultivation of red, green and light green leaf baby lettuces (Lactuca sativa L.) grown under natural illumination and high-pressure sodium (HPS) lamps (16-h; PPFD-170 μmol m(-2)s(-1)) during different growing season. Supplementary lighting from blue 455/470 nm and green 505/530 nm LEDs was applied (16-h; PPFD-30 μmol m(-2)s(-1)). Our results showed that to achieve solely a positive effect is complicated, because metabolism of antioxidant properties in lettuce depended on multicomponent exposure of variety, light quality or seasonality. The general trend of a greater positive effect of supplemental LED components on the vitamin C and tocopherol contents was in order: 535>505>455>470 nm; on the total phenol content: 505>535=470>455 nm; on the DPPH free-radical scavenging capacity: 535=470>505>455 nm; on the total anthocyanins: 505>455>470>535 nm. Further investigations are needed for understanding the mechanism and interaction between antioxidants and light signal transduction pathways.
authors.affiliation: Institute of Horticulture, Lithuanian Research Centre for Agriculture and Forestry, Kaunas Str. 30, LT-54333 Babtai, Kaunas Distr., Lithuania.
authors.forename: Giedrė
authors.initials: G
authors.lastname: Samuolienė
authors.forename: Ramūnas
authors.initials: R
authors.lastname: Sirtautas
authors.forename: Aušra
authors.initials: A
authors.lastname: Brazaitytė
authors.forename: Pavelas
authors.initials: P
authors.lastname: Duchovskis
mesh_terms: D000975:Antioxidants / Q000032:analysis; D018545:Lactuca / Q000737:chemistry*; D008029:Lighting / Q000379:methods*; D018515:Plant Leaves / Q000737:chemistry*; D013649:Taste
chemical_list: D000975:Antioxidants