Flavonolignans of Milk Thistle (Silybum marianum L.) Seeds Affected by Fertilization Type and Plant Genotype

The fertilization method and plant genotype are two important factors affecting the active ingredients of medicinal plants. Milk thistle (Silybum marianum L.) is one of the most widely distributed medicinal plants worldwide that its seeds have been used widely for treatment of toxic liver damage. In this research, effects of genotype and fertilization type on the quality of milk thistle seeds were investigated. Seeds of two genotypes of milk thistle (Hungarian (A1) and Iranian (A2) genotypes) were cultured and eight fertilization treatments (F1= control treatment (no fertilizer), F2= cow manure, F3= NPK fertilizer, F4= mycorrhizal (Glomus mosseae) inoculation, F5= combination of nitroxin, bio-sulfur and bio-superphosphate, F6= combination of NPK fertilizer and cow manure, F7= combination of arbuscular mycorrhizal fungi inoculation and cow manure, F8= nano-iron chelate) were used. Traits such as seed yield, oil content and the amount of flavonolignans in the seeds were measured. The results showed that the maximum seed yield was obtained in A2*F4 treatment (1376.54 kg h-1) and the lowest was related to A1*F1 (508.99 kg h-1). The average oil content of the samples was about 2.4 mg g-1 and no significant difference was observed. The results of HPLC analysis showed that the mycorrhizal inoculation (F4) in both genotypes led to the achievement of the maximum amount of most important flavonolignans such as silymarin, taxifolin, silydianin, isosilybin B (18.79, 2.80, 5.02 and 4.73 mg g-1, respectively) and an acceptable amount of isosilybin A (2.72 mg g-1), but A1*F4 treatment yielded the best results. In conclusion, use of mycorrhizal inoculation is an effective practice for production of milk thistle seeds with high quality.