In vitro Development of Mature Fagus Sylvatica L. Buds. I. The Effect of Medium and Plant Growth Regulators on Bud Growth and Protein Profiles

A procedure for aseptic in vitro culture of beech buds ( Fagus sylvatica L.) from adult trees, for various periods of time, was developed. When cultured under optimal conditions, dormancy break of buds occurred in culture and they sprouted in vitro, resulting in significant shoot elongation and leaf expansion. Aspen culture medium enhanced bud development, as compared with Murashige and Skoog medium. Indole-3-acetic acid, gibberellic acid (GA 3) and zeatin enhanced shoot elongation and leaf growth. All 3 hormones combined supported growth of cultured isolated beech buds, but GA 3 may play a specific role in supporting bud growth. Solubilized protein profiles of beech buds were analyzed by one-dimensional SDS-polyacrylamide gel electrophoresis. Distinct changes in several polypeptides were detected between dormant and in vitro growing buds, the latter showing a decrease in the intensity of many polypeptide bands. Differential growth rates of buds on two culture media were accompanied by a change in the amount of a 55 kD polypeptide, and an intense band at approximately 62 kD is evident in buds cultured with 2-isopentenyladenine. The data suggest that bud culture can be used to monitor and detect physiological and hormonal processes that control forest tree growth, and that direct supply of growth regulators can induce growth in otherwise quiescent buds.