Assessment of nutritional properties of Valerianella locusta plants growing in indoor vertical farms under different lighting conditions

Vertical farms (VFs) are controlled indoor growing systems that facilitate the cultivation of leafy vegetables in urban areas, maximizing yield m^‑2. Plants are usually hydroponically cultivated in VFs, reducing irrigation needs, but on the other hand, VFs have high energy demands for lighting operation.
Thus, it is valuable to specify the optimum light conditions that offer desirable traits to the plants while the VFs are energy efficient.
The aim of this study was to evaluate biochemical factors of corn salad (Valerianella locusta) plants, such as ascorbic acid, total polyphenol content, antioxidants and nitrate content under different lighting conditions.
Two different light qualities were tested; a) white, and b) blue, red and NIR-infrared (B-R-NIR) parts of the spectrum.
The tested treatments under each spectra combination had a PPFD of 250 μmol m^‑2 s^‑1 and 3 different photoperiods of 16, 14 and 12 h day^‑1 of light, resulting in different daily light integrals, DLI of 14.4, 12.6 and 10.8 mol m^‑2 day^‑1, respectively.
Results showed that ascorbic acid concentration reached maximum levels at 14 h daylight, under white light, and under all conditions in B-R-NIR light.
Total polyphenols were at the highest concentration under 16 h of daylight at both light qualities, while antioxidant activity reached its peak at 12 h of white light and 16 h B-R-NIR light.
Nitrate content was lowest at maximum daylight.
As a conclusion, optimal biochemical characteristics of the plants, like high ascorbic acid, polyphenols and antioxidants but low nitrate content, were observed under the condition of 16 h of light per day, under B-R-NIR light quality, while the second-best condition was 14 h of B-R-NIR light.
Energy consumption was doubled at 16 h compared to 14 h of daylight, thus the second condition was considered optimal.

International Symposium on New Technologies for Sustainable Greenhouse Systems: GreenSys2023

N. Mougiou, S. Didos, I. Bouzouka, D.D. Avgoustaki, A. Argiriou

biochemical analysis, nitrates, antioxidants, polyphenols, vitamin C, daily light integral, corn salad

https://doi.org/10.17660/ActaHortic.2025.1426.27