Abstract: The isolated xylem of Euonymus bungeanus Maxim. has been successfully induced into plantlets for the first time under culture in vitro. The percentage of plantlet formation was about 8%. The process of cultivation was able to be devided into three stages: 1. To induce the formation of callus, for which the medium H showed the best effect, but it was necessary to supply with the different concentration of 2,4-D, NAA or BA. 2. The differentiation of the callus into plantlets, for which the medium H or MS+BA 2 mg/l+KT 0.5–1.0 mg/l+NAA 0.2 mg/l was most promising and 3. The growth of plantlets, for which the medium White+ NAA 0.1 mg/l+IAA 0.1/1 was most suitable. Further observations based on the histology showed that callus was produced from the ray cells. Meristematic tissue appeared as a discontinuous and more or less regularly arranged bands. Later, some of them were arranged in a cirle like in the normal stem. However, the newly formed meristematic tissue did not produce normal vascular tissues. They could only differentiate into tracheid-like elements on one side and no sieve-like elements differentiatedon the opposite side. In addition, there might be appeared nest-like tracheid mass in groups. The adventitious buds and roots derived from the excised xylem which followed the normal process of ontogenesis, i.e. the buds were from exogenous origin and the roots, endogenous origin.

Key words: the xylem of Euonymus bungeanus Maxim., in Vitro, Morphogenesis.