مهرانگیز جوکار

Milk thistle is one of the most important medicinal plants of Asteracea family that had very medicinal poperties. The seeds of this plant consist of silymarin (a flavonolignan complex) and 20–35% fatty acids, including linoleic acid. Silymarin is a complex mixture of polyphenolic molecules, including seven closely related flavonolignans (silybin A, silybin B, isosilybin A, isosilybin B, silychristin, isosilychristin, silydianin) and one flavonoid (taxifolin). This study was conducted to evaluate the physiological and biochemical mechanisms of seed priming treatment which improved the quality of milk thistle (Silybum marianum) seeds. . This step was conducted in Agricultural Biotechnology Research Institute of Iran (ABRII) and its experimental design was arranged in a completely randomized design with three replications and four factors. The factors were first: genotype (Amol and Majar), second: primed and non-primed seeds, third: salinity (150 mM) and controlled (non-salinity) conditions and the fourth: time of sampling in 24 and 96 hours after sowing. Biochemical indices that were analyzed in this step included malondialdehyde (MDA), alpha, gama and delta tocopherol levels (vitamin E isomers), soluble sugars total using advanced analyzing methods. Seed priming significantly increased alpha and gama tocopherol level under salinity conditions in both genotypes and significantly decreased MDA level. The level of alpha, gama and delta tocopherol were greater in Majar than in Amol. Also, MDA level decreased 24% in primed seeds in comparison to non-primed seeds under salinity stress condition. The effect of seed priming under controlled condition was so considerable that decreased MDA level 11% in primed seeds in comparison to non-primed seeds. From imbibition to germination, alpha, gama and delta tocopherol levels increased and MDA level decreased. The results of evaluating soluble sugars showed that seed priming increased 13% this time under salinity stress condition a