Induction of adventitious buds and sprouts on birch seedlings (Betulapendula Roth and B. pubescens Ehrh.)

Abstract

The ability of decapitated Betulapendula Roth and Betulapubescens Ehrh. seedlings to form adventitious buds and sprouts was investigated under both laboratory and field conditions, and the occurrence of adventitious buds on stumps of naturally growing adult B. pubescens was also studied. However, all the buds on the stumps proved to be axillary in origin. Disbudding of seedlings induced the development of callus and adventitious bud differentiation in both species. The morphogenetic ability of B. pendula seemed to be very much better than that of B. pubescens, while young plants produced adventitious buds sooner and in greater numbers than older ones. Regeneration occurred both in greenhouses and in the field. Adventitious buds were observed in the callus that formed between the phloem and wood and in wounded areas of the stem about 40 days after decapitation, and some started to sprout about 20 days later. The first leaves of the sprouts were small and structurally simple. The results show that although B. pubescens and B. pendula do not normally produce adventitious buds, they have preserved the ability to form them. Regeneration from these buds is probably important for survival in certain special cases when the seedling is not able to sprout from its dormant buds for some reason.