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The present study aimed to investigate the effect of some bio-elicitors and silver nitrate on the content of secondary metabolites in calli derived from leaf explants of silybum marianum. In this research, the best callus was achieved on MS medium containing KIN, thus this medium was chosen for further experiment. In the second experiment, leaf explants were cultured in a selected hormone-regulated medium. After 8 weeks of callus growth, bio elicitors including yeast Yarrowia lipolytica, fungus Aspergillus niger, and bacterium Pseudomonas putida in combination with silver nitrate as a non-living elicitor were added to the leaf-derived calli. Ten days after treatment, the phenolic compound content, antioxidant capacity, silymarin content, and PAL enzyme activity in the calli were measured. The results indicate that the simultaneous application of Yarrowia yeast and silver nitrate led to an improvement in the content of phenolic derivatives, silymarin, and PAL enzyme activity, and this was significant compared to other elicitors both with silver nitrate and without it. The researchers of this experiment suggest that the combined use of bio-elicitors especially Yarrowia lipolytica yeast, and silver nitrateinduces higher synthesis of medicinal metabolites in calli derived from leaf explants. 

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Ferula gummosa Boiss. as a valuable pharmaceutical and industrial plant grows in Iran. In order to minimize seed dormancy period and micropropagation, callus induction and embryogenesis were evaluated. The plantlets of the seeds were separated and cultured in the 1/2 MS medium. After 14 days, root, hypocotyl, cotyledon and leaf explants were separated. Then they were transferred to the basal MS medium containing different concentrations of growth regulators. Different developmental stages of somatic embryos were evaluated. Seedlings 2-3 days after locating in 1/2 MS medium germinated and whole plantlets were obtained after 12 days. In the callus induction phase growth regulator composition 1.5 mgl^-1 of NAA and 0.5 mgl^-1 of BA with root explants had proper results. In the somatic embryogenesis phase MS medium containing 0.5 mgl^-1 of 2,4-D accompanied by 1 mgl^-1 of BA lead to desirable results. Via taken sections from the embryos, different developmental stages of somatic embryos including pre-embryo, globular, heart shaped, torpedo and cotyledonary embryo were observed. In vitro culture of embryo to accelerate germination and elimination of long dormancy period and using this optimized method are strongly suggested for micropropagation of this plant so this valuable endemic plant may survive from extinction, too.