Effects of Lichen Metabolites Atranorin, Lobaric Acid, and Usnic Acid on Growth and Biomass of Rocket (Eruca sativa Mill.) Microgreens

Year 2025, Volume: 8 Issue: 2, 93 - 100, 29.12.2025

Yazgı Doğa Atıcı , Muhammet Doğan , Buğrahan Emsen

https://doi.org/10.46239/ejbcs.1816758

Abstract

Microgreens are young, nutrient-rich seedlings that have gained considerable attention for their high nutritional value and short cultivation period. This study investigated the effects of three lichen-derived secondary metabolites – atranorin, lobaric acid, and usnic acid – at five different concentrations (2, 4, 6, 8, and 10 mg/L) on the growth and biomass parameters of Eruca sativa Mill. microgreens, specifically shoot length, root length, and fresh and dry weight. Morphological observations indicated that germination began on the third day, and seedlings reached the typical microgreen stage with fully expanded cotyledons and dark green true leaves by the eighth day. Results revealed that all three metabolites exhibited a dose-dependent response pattern. Atranorin and lobaric acid showed optimal stimulation of shoot and root growth at moderate concentrations (4–6 mg/L), while usnic acid demonstrated maximum growth promotion at higher doses (8–10 mg/L). Low concentrations (2 mg/L) generally caused mild inhibitory effects on elongation and biomass accumulation. Heatmap and clustering analyses confirmed two distinct response groups: low-dose inhibition and mid-to-high-dose stimulation. These findings suggest that lichen metabolites can act as potential natural biostimulants for microgreen cultivation when applied at appropriate concentrations, supporting sustainable and environmentally friendly production systems.

Keywords

Atranorin , Eruca sativa , growth stimulation , lichen secondary metabolites , lobaric acid , microgreens , usnic acid

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