Precultivation of young seedlings under different color shades modifies the accumulation of phenolic compounds in Cichorium leaves in later growth phases

Manipulation of spectral composition has been found to be an efficient way to influence the growth and quality of plant production in protected or controlled environments. The aim of this study was to compare the short- and long-term effects of early pretreatment with different color shades on the composition of phenolic compounds and photosynthetic pigments in Cichorium leaves. The analyses conducted immediately after color shade pretreatments at ˜40 μmol m−²s−1 (blue, red orange, white) indicated lower values of chlorophyll, anthocyanin and flavonoid indices, as well as of the majority of flavonoids, compared to those in the same plants subsequently grown for 4 weeks under higher white light with an intensity of ˜320 μmol m−²s−1. However, we observed significant differences in the contents of phenolics and pigments depending on previous color shade pretreatment in plants grown for 4 weeks in the same environment and in leaves grown during this period. The most significant effect was observed in plants pretreated with orange light, in which levels of isorhamnetin, its derivatives and feruloyl malate were increased, and kaempferol-3-(6”-acetyl)-glucoside levels were significantly decreased. Blue light pretreatment led to lower values of chlorogenic acid, caftaric acid and isorhamnetin-3-(6”-acetyl)-glucoside but a higher content of isorhamnetin-3-glucoside. Red light led to an increase in quercetin derivatives. Compared to plants grown under constant conditions, low light in the early growth phases led to the upregulation of feruloyl malate, caffeoyl malate and kaempferol derivatives. Nondestructive measurements enabled the identification of significant effects of light pretreatment on the chlorophyll contents, as well as the accumulation of flavonoids and anthocyanins in the epidermal leaf layer. The induction of specific metabolites influenced by the acclimation of plants to colored light environments may emphasize the environment‐induced biochemical responses associated with the remarkable plasticity of phenylpropanoid metabolism.