Teresa Hazubska-Przybył, Paweł Chmielarz, Krystyna Bojarczuk
In vitro responses of various explants of Fagus sylvatica
Dendrobiology 2015, vol. 73: 135-144
Abstract: There are limited published data on in vitro reproduction of Fagus sylvatica L. (European beech). This study was aimed to determine the efficiency of induction of somatic embryogenesis or organogenesis of beech from different types of explants in various culture conditions. Explants derived from immature, fresh seeds (collected in 2011 and 2013) and from mature seeds, stored at –10ºC and some stratified at 3ºC, were placed on induction media with various combinations of plant growth regulators: zeatin, 2,4-dichlorophenoxyacetic acid (2,4-D) and/or benzyladenine (BA). Initial cultures were kept in darkness or weak light (white fluorescent or blue-red LED). Limited success has been achieved in initiation of somatic embryogenesis. We obtained friable, yellow-white callus with characteristic PEM-like structures (cPEM-ls, from embryonic axes or fragments of immature embryos with embryonic axes), which may be an early developmental stage of embryogenic callus of Fagus sylvatica. This type of callus regenerated from explants incubated in darkness, mainly on WPM medium with addition of 6.8 μM zeatin or WPM and MSG media with 9.1 μM 2,4-D and 2.2 μM BA. The highest frequency of regeneration of callus with cPEM-ls was 5%. Instead, we succeeded to induce organogenesis from both immature and mature zygotic embryos and from embryonic axes. The best results were obtained for mature zygotic embryos incubated on ½WPM medium (half-strength Woody Plant Medium) with 9.1 μM 2,4-D and 2.2 μM BA. Adventitious buds were regenerated on up to 15% of the explants. The induced buds developed into shoots, enabling us to establish tissue cultures of beech. Induction of organogenesis from the tested explants was more efficient than induction of somatic embryogenesis.
Additional key words: European beech, micropropagation, culture conditions, tissue culture