リンゴわい性台木の根ざし増殖に関する研究

Abstract

1. Root cutting was evaluated as a commercial propagation technique of the dwarf apple stock cv. East Mailing VII by examining the histological aspects and physiological traits of the cutting material.2. All the cutting material produced adventitious buds and roots regardless of its size (both length and diameter) and sampling location on the root system. However, consistent formation of these organs was achieved only when root pieces more than 10cm in length were used.3. Nursery stocks were produced more efficiently by root cutting than by either traditional mound layering or modified bowed-branch layering.4. Adventitious bud primordia became differentiated in the cortex of root pieces as the regeneration of cutting material progressed. The cells of bud primordia were smaller than those of ordinary parenchyma and distinguishable morphologically from the surrounding tissues. They could be classified arbitrarily into five categories, each corresponding to their developmental stage.5. Adventitious bud formation was stimulated by the pretreatment of cutting material with 50ppm 6-benzylamino purine solution. By paper chromatography, the extract from the cutting pieces showed considerably high cytokinin activity in the same zone as zeatin. The activity gradually increased until adventitious bud primordia manifested themselves, though it was suppressed in the cutting pieces where bud primordium failed to differentiate. Thus, it was suggested that there is a close relationship between bud formation and cytokinin activity of the cutting material.