シンビジウムの偽球茎への暗黒処理がえき芽の発育に及ぼす影響

Abstract

Risk of mutations is a serious problem in propagation in vitro. Traditional vegetative propagation by division is a genetically safe clonal propagation method, although multiplication speed is slow. To improve the multiplication rate of Cymbidium by division, effects of dark treatment of pseudobulbs on sprouting of lateral buds and subsequent growth were investigated. Dark treatment promoted new shoot development from lateral buds in all cultivars. The effect was prominent in lead bulbs which in all cultivars developed shoots. Although the effect of dark treatment was less effective in the 1-and 2-year-old pseudobulbs, these bulbs sprouted more shoots than lead ones. Effects of dark treatment became obvious four or five months later after the start of the treatment because it inhibited defoliation from two-and one-year old pseudobulbs and stimulated healthy root development. The increased number of roots could be responsible for new shoot development. Cym. Hong Gui developed flower stalks from back pseudobulbs and bloomed in the dark and light. The rate of flower stalk development was slow in plants which produced numerous shoots. These findings indicate that dark treatment of pseudobulbs could hasten clonal multiplication of Cymbidium by division.