In vitro responses of various explants of Fagus sylvatica

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.

Current status of the cryopreservation of embryogenic material of woody species

“…Another cryopreservation method, by means of desiccation over silica gel (see section 4.3) of the PEMs has proven to be successful in Picea (Hazubska-Przybył et al, 2010;Hazubska-Przybył et al, 2013). In this sense, desiccation (Percy et al, 2001), together with vitrification or encapsulation (Gale et al, 2008) has been tested for cryopreservation of somatic embryos at different developmental stages.…”

A Review of Propagation and Restoration Techniques for American Beech and Their Current and Future Application in Mitigation of Beech Bark Disease

“…plantlets can be produced through organogenesis [65,66] but no methods have been published to reliably transfer them to soil. Beech embryos can be created through embryogenesis, but again no process has been developed for successful transfer [67]. Micropropagation methods for F. grandifolia have been explored [65,68], though no method of propagating and growing plants through micropropagation has proven reliably successful.…”

Tree somatic embryogenesis in science and forestry

“…Currently, a significant part of tree somatic embryogenesis research is focused on tree development, starting from the induction of somatic embryos and finishing with the acclimation of the developed somatic seedlings to natural conditions. In trees, somatic embryogenesis is a highly complex process (Roberts et al, 1991;Bozhkov et al, 2002;Hazubska-Przybył & Bojarczuk, 2008) and is often difficult to trigger (Hazubska-Przybył et al, 2015). Somatic embryogenesis is divided into several steps: culture initiation, proliferation, maturation and in vitro germination.…”

“…A high adaptation level to ex vitro conditions for Larix decidua was achieved, whereas for the other species, this process has been much more difficult (Szczygieł et al, 2007). In contrast, attempts to achieve somatic embryogenesis of broad-leaved tree species, e.g., oak and beech (Olszewska, 2000;Hazubska-Przybył et al, 2015), have not yielded positive results, although there was recently new information concerning the initiation of somatic embryogenesis from leaves derived from in vitro cultures established from the shoots of thirty-year-old Quercus robur trees (Kotlarski et al, 2015). In some countries, selected species of oak trees have been successfully propagated using this method (Wilhelm, 2000;Vieitez et al, 2012); while in the case of beech, research on somatic embryogenesis has been rarely undertaken (Vieitez et al, 1992;Naujoks, 2003).…”

“…In some countries, selected species of oak trees have been successfully propagated using this method (Wilhelm, 2000;Vieitez et al, 2012); while in the case of beech, research on somatic embryogenesis has been rarely undertaken (Vieitez et al, 1992;Naujoks, 2003). The reason is most likely the general difficulty to achieve vegetative reproduction of this tree species (Hazubska-Przybył et al, 2015).…”