Light Modulation of Photosynthate Accumulation in Microgreens Grown in a Controlled Environment During Storage

Abstract

Light intensity and spectral composition are the main parameters that may be modulated to further affect plant nutritional value and shelf life. The current study aimed to assess how variations in spectral composition and light intensity affect sugar accumulation during the storage of two popular microgreens cultivated in a greenhouse under controlled conditions. Thus, in this study, amaranth (Amaranthus tricolor) and mustard (Brassica juncea) microgreens were grown in a greenhouse at 17/20 ± 3 °C and a 16 h photoperiod was maintained. (I) Four LED light intensities were set: 100, 150, 200, and 250 µmol m−2 s−1 while using 4000 K white LED lighting. (II) Maintaining 250 µmol m−2 s−1 the effect of spectrac composition: B75.6%:R24.2%:W0.02%/R88.9%:B11.1%/and R77.6%:W9.9%:B3.5% was evaluated. After 10 days from germination, microgreens were harvested and stored in the dark or under white LED light at +4 °C. Samples were collected on D0, D1, D3, and D5 days of postharvest storage. The results revealed that a wide spectrum of 250 µmol m−2 s−1 PPFD and R88.9%:B11.1% growing conditions produced the highest sugar content, achieving a balance between increased sugar accumulation and reduced deterioration during storage, ultimately extending shelf life.