Enhancing the production of active compounds in wild Silybum marianum L. using biofertilizers, conventional and nano-fertilizers: A comparative study under field cultivation conditions

Abstract

A field experiment was conducted on wild thistle (Silybum marianum L.) at the College of Agriculture, Al-Qasim Green University. This study employed a completely randomized design (CRD) with four treatments to investigate the effect of foliar fertilization with biostimulants, in addition to conventional and nano-enriched NPK fertilizers, on the synthesis of secondary metabolites and antioxidant activity during the winter of 2024. The initial treatment (T0) was water spraying. In treatment T1, a standard NPK fertilizer was sprayed at a concentration of 2 g/L. The third treatment (T2) involved spraying a nano-enriched NPK fertilizer at a concentration of 2 g/L. In the fourth treatment (T3), a biostimulant was sprayed at a concentration of 2 mL/L, in addition to the wild thistle treatment. High-performance liquid chromatography (HPLC) analysis was performed on the plants, and the data showed that wild thistle plants outperformed those sprayed with water alone. The T3 plants were found to outperform other produced plants and natural samples in all measured parameters, including total phenolic compounds, flavonoids, and alkaloids. T3 plants contained higher levels of glutathione (GSH), cysteine, methionine, gallic acid, apigenin, kaempferol, and ferulic acid (192.1, 59.9, and 86.9 ppm, 125.9, 80.9, 85.4, and 97.4 mg/g, respectively), indicating their antioxidant activity. This research reveals that biostimulants are essential for increasing crop productivity and plant selection in modern agriculture.