The Effect of Head Lettuce (Lactuca sativa var. capitata L.) Cultivation Under Glass with a Light Spectrum-Modifying Luminophore on Crop Traits

The present study aimed to evaluate crop characteristics, including morpho-anatomical features and nutritional and health-promoting composition, of head lettuce cultivated in greenhouses covered with transparent glass (control) and glass containing a red luminophore (red). The plant material comprised two lettuce types: butterhead and iceberg. Alterations were observed in head dimensions, morphology, and leaf mesophyll structure of plants from the red greenhouse. Butterhead lettuce plants exhibited unaltered head area under tested conditions but displayed a reduction in accumulated sugars and amino acids, resulting in a decline in dry matter content. Conversely, an increase in soluble and insoluble sugars and amino acid content, along with no change in nitrate content, was observed in iceberg lettuce. However, the growth intensity of iceberg lettuce decreased, while its dry matter content increased. Moreover, phenols and vitamin C concentration were lower in iceberg lettuce than in the butterhead one. In the red greenhouse, the phenolic content declined in both lettuce types, but vitamin C levels were reduced in butterhead lettuce and remained unchanged in iceberg lettuce. The data clearly demonstrate that the extent of variation in crop characteristics observed in lettuce cultivated in the red greenhouse depended on the tested lettuce type, with notable alterations occurring in iceberg lettuce.