The Effect of Mycorrhizal Fungus, Humic Acid and Vermicompost on Biochemical and Yield Properties of Silybum marianum

milk thistle (Silybum marianum) is one of the most popular medicinal plants of most developed countries. In the past, milk thistle leaves has been used to treat biliary and gastrointestinal diseases. It has valuable effects on the prevention and treatment of long-term complications of diabetes, renal failure and nerve cell disorders. Silibinin is the most important flavonoid in the plant that plays an important role in prostate cancer treatment. Humic Materials are part of the organic matter of humus soils resulting from the physical, chemical and microbiological deformation or homophication of biomolecules in the soil. This study aims at investigating the effect of organic and biological fertilizers including humic acid, vermicompost and two species of mycorrhizal fungi on physiological and morphological traits of Silybum marianum.

This study was conducted in the spring in Gorgan. This study was conducted as factorial experiments using Completely Randomized Design (CRD). Treatments included four levels of vermicompost (0, 25, 50, and 75%), four levels of humic acid fertilizer (0, 25, 50 and 75 mg / L) and two species of mycorrhizal fungi (Glomus mosseae and Glomus intraradices). Yield, 1000 - grain weight, leaf area, capitule number, chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, soluble sugars and protein were measured in the plant. All measurements were carried out in three replications, and mean comparisons were made through the Duncan test (P<0.05) using SPSS-22 software package.

The results of data analysis of variance showed that all the studied properties are affected by the interaction of the applied treatments. The highest Silybum marianum yield was obtained in Glomus mosseae third level vermicompost and first humic acid level equal to 2296 kg / ha. Also, the lowest grain yield was obtained in the control treatment (435 kg / ha). The reason for the increase in yield can be attributed to the supply of nutrients, water supply and improving the respiratory status of the plant due to the use of organic and biological fertilizers. Also, the presence of mycorrhiza fungi and vermicompost has improved the physical condition of the soil and increased the ability of the plant to use soil water. The highest leaf area (3.96 cm2) was observed in the fourth level of humic acid (75 mg / L) and vermicompost (75%) in both types of Glomus mosseae and Glomus intraradices. The highest amount of total chlorophyll in the plant (15.26 mg / g fresh weight) was related to humic acid 50 g / l + mycorrhizal fungus Glomus mosseae at 25% vermicompost level. Mycorrhizal fungus improves nitrogen uptake, which plays a key role in plant chlorophyll structure. On the other hand, nitrogen is the most important element in protein synthesis, which is in favorable condition with the increase of mycorrhizal fungus and leads to an increase in the amount of protein and soluble sugar. The results have shown that use of humic acid has positive effects on the studied plant characteristics. The highest protein (3.65 mg / wet weight) was obtained in the third level of humic acid and Glomus intraradices and the lowest protein (0.92 mg /wet weight) in control treatment.

The use of organic compounds as fertilizer improves the physical, chemical and biological properties of soil. Also increases plant growth by providing the plant with the necessary elements. In general, the results showed that the use of organic and bio-fertilizers can improve the status of Silybum marianum and these compounds can reduce the use of chemical fertilizers to prevent the adverse effects of these fertilizers on human health and the environment.