Effects of different ectomycorrhizal fungi on somatic embryogenesis of Abies cephalonica Loud

The effects of ectomycorrhizal (ECM) fungi, including Laccaria bicolor (Maire) Orton, Laccaria laccata (Scop., Fr.) Berk. and Br., along with two strains of Pisolithus tinctorius (Pers.) Coker and Couch, on the proliferation and subsequent maturation of two embryogenic cell lines of Abies cephalonica Loud., designated lines 6 and 8, were investigated. In the presence of these ECM fungi, the proliferation of both embryogenic cell lines was inhibited. L. bicolor and P. tinctorius strain 2 resulted in the highest inhibition rates. On the other hand, cultivation of embryogenic cultures along with ECM fungi, termed a dual culture, increased radial growth of both P. tinctorius strains; whereas, L. bicolor and L. laccata did not grow as well in the presence of embryogenic cell masses. The dual culture during the proliferation period of embryogenic cells, however, enhanced the subsequent embryo formation and maturation of A. cephalonica; i.e. the capability of embryogenic cell lines to form somatic embryos as well as increasing the mean number of somatic embryos per 1 g fresh weight of embryogenic cell mass. However, levels of responses were highly dependent on the interaction between the specific embryogenic cell line and fungal strain.