Abstract
Rhizome-tips of Cymbidium goeringii REICHB. F. cultured on the basal medium (KNUDSON′s C with NITSCH′s microelement), developed into rhizomes without the shoot formation. However, the addition of 10mg/l kinetin to the medium induced shoot formation. Histological studies were carried out with the shoot formation in order to analyze the rhizome-shoot differentiation. Results of the observation were summarized as follows:
During the growth of the rhizome, the apical meristem remained to a primitive appearance. A few mitotic figure was observed within the apical meristem from which small leaf primordia were porduced and developed into scale-like leaves. The cells in the leaf primordia appeared to be less meristematic and considerably vacuolated. A remarkable expansion of the cells in the subapical region could be responsible for elongation of the rhizome.
In the course of the shoot formation, on the contrary, leaf primordia were produced with a short plastochron then developed into leaves with vascular tissues. Relatively abundant mitotic figures were observed not only within the apical meristem but also in the lower part and the leaf primordia. The cells in the leaf primordia and the subapical region were smaller and less vacuolated than those of the rhizome.
