CRYOPRESERVATION OF EMBRYONIC AXES OF FERULA GUMMOSA: A TOOL FOR GERMPLASM CONSERVATION AND GERMINATION IMPROVEMENT

Cryopreservation (protecting in liquid nitrogen (LN) -196°C) represents the only safe and cost-effective option for long-term conservation of germplasm of non-orthodox seed species, vegetatively propagated species and of biotechnology products. Classical cryopreservation techniques, which are based on freeze-induced dehydration, are mainly employed for freezing undifferentiated cultures and apices of cold-tolerant species. New cryopreservation techniques which are based on vitrification of internal solutes are successfully employed with all explant types, including cell suspensions and calluses, apics and somatic and zygotic embryos of temperate and tropical species. This technique was used for conservation of seeds and embryonic axes of Ferula gummosa which is an endemic plant of Iran with medical and industrial applications. To achieve the torpedo stage, seeds of Ferula were cultured in the media and stored in 4°C. The embryonic axes were then pre-treated by 0.7 sucrose cultures and exposed to LN with two encapsulation-dehydration (E/N) and vitrification methods. Seeds, extracted, embryonic axes and 30-day-cultured seeds were successfully cryopreserved by encapsulation-dehydration and vitrification methods. The most survival percentage was obtained when the encapsulation-dehydration method was applied for crypreservation of embryos and the results showed 50% of its superiority to vitrification method. Moreover, the germination of embryonic axes were more progressed in comparison with Ferula seeds natural germination. According to high percentage of survival in E/N method after cryopreservation, this technique is suggested as an efficient way for conservation of Ferula gummosa embryonic axes.