Effects of soil conductivity on properties of saffron corms and in vitro production of its style explants

Saffron is the dried stigmas of Crocus sativus L., a member of the Iridaceae family which is propagated by means of corms. Corms are faced with many stresses in soil. Therefore, it is important to reduce these stresses and improve the quantity of saffron production. Biotic and abiotic stresses disrupt the metabolic balance of cells; thereby, resulting in accumulation of reactive oxygen species (ROS) which cause oxidative damage. In this study, the effect of soil electrical conductivity (EC) on biochemical indicators of corms, the percentages of callus formation and stigma-like structures (SLSs) on calli were investigated. In order to obtain calli and SLSs, immature style explants from floral buds of corms were collected from three regions (Shahroud, Mardabad and Torbat Heydarieh) and used for tissue culture. Style explants were separated first from the immature floral buds, then sterilized and used for tissue culture. Biochemical analysis of calli with SLSs including malondialdehyde (MDA) and proline contents, antioxidant enzymes activities and polysaccharides and reducing sugars contents were investigated and compared. Moreover, sodium and potassium ions content and EC of soils of the three regions were investigated. The results indicated that corms from Shahroud with the highest level of EC soil showed more imposed stress than that from Torbat Heidariye and Mardabad but the calli percentage and number of SLSs of Mardabad’s were higher than those of the other two respectively. In this study, a close relationship between soil EC and in vitro production of saffron with a short glance on epigenetic modification was postulated.