Somatic embryogenesis of selected spruce species (Picea abies, P. omorika, P. pungens 'Glauca' and P. breweriana)

Abstract

Somatic embryogenesis was studied in four spruce species (Picea abies, P. omorika, P. pungens 'Glauca' and P. brewenana) to determine if this method can be used for in vitro propagation of coniferous trees. The highest frequency of initiation of embryogenic tissue was obtained when mature zygotic embryos were used as explants. It ranged then from 10.8% (P. brewenana) to 23.75% (P. omorika and P. pungens 'Glauca'). The frequency of embryogenic tissue initiation was strongly affected by medium composition, i.e. addition of appropriate auxins (2,4-D, NAA, Picloram) and sucrose concentration (10-20 g^-1"1). A lower frequency was obtained in Picea omorika (10%) when megagametophytes (endosperms with immature zygotic embryos) were used as explants. No emryogenic tissue was produced from hypocotyls, cotyledons and needles. A satisfactory frequency was achieved with the use of somatic embryos of Picea abies (30%). The proliferation of embryogenic cell lines of spruces was affected by medium type. The experiments resulted in production of somatic plantlets of P. abies and P. omorika. This enables the application of this method of spruce micropropagation for genetic and breeding research or for nursery production.