Effect of medium, explants and BA on somatic embryogenesis induction in tow Iranian native orchids

Temperate terrestrial orchids are an important group in Orchidaceae family that in recent years they could to attract attention in horticulture world. Epipactis veraterifolia and Dactylorhizba umbrosa are members of Iranian native temperate terrestrial orchids. Unfortunately, the low propagation, high price and high demand in the market interest, is due to collect them from the wild habitat. As a result, their number has decreased and some species are at risk of extinction.Most of temperate terrestrial orchids are endangered species. On the other hand, despite progress for micropropagation and in vitro cultivation of some orchids, there are a few reports in temperate terrestrial orchids. Somatic embryogenesis has high potential for large-scale micropropagation especially for plants with specific reproduction cycle (as orchids). To establish an efficient method, a study was conducted using somatic embryogenesis as a rapid vegetative propagation technique for conservation. The aim of this report was to finding better condition for somatic embryogenesis induction of this native species, for mass propagation in large scale.
In this study, two levels of BA (0 and 3 mg / l) and four different culture media (1/2 MS , 1/4 MS , 1/8MS , FAST) were investigated for two Iranian native orchids regeneration via direct somatic embryogenesis. Hence, four different explant types of (leaf, stem, crown, protocorms) Epipactis veratrifolia and two explants of (leaf, crown) Dactylorihza umbrosa were used.
Results show that there were no significant differences in somatic embryogenesis of E. veratrifolia among medium treatments, but BA and different explants interaction was significant and protocorm explants by produced 13 embryos in each explant had the highest embryogenesis frequency in 1/4 MS medium contain BA (3 mg / l). There was significant difference among medium treatments in D.umbrosa and FAST medium had the best response. Also crown explants had the highest embryogenesis frequency (2.66 embryos per explants). The results indicated a positive effect of BA (3 mg/l (on the embryogenesis of this species.
The observation showed the positive effect of 3 mg/l BA in both species. Therefore, the usage of BA and study on the effect of different dosage of this hormone were suggested. In Epipactis veratrifolia there was no significant difference between the media, while FAST medium has significant difference with other media in Dactylorihza umbrosa species. Protocorm explants in Epipactis . veratrifolia and crown explants in Dactylorhiza . umbrosa showed the most efficient explants. In both species leaf explants has no response.