Abstract
A strain "D1" of carrot root tissue was repeatedly subcultured on the standard medium containing 0.5 percent yeast extract and 1 mg/1. 2, 4-D. On that medium the culture grew rapidly in the form of undifferentiated tissue masses. After the transplanting of the cultures into the standard medium lacking 2, 4-D), they developed the tissue nodules from which roots arose. While with the cultures transplanted into the media containing 0.5∼2.0 percent casein acid hydrolysate, adventive embryos were formed. And yet it was cleared up that the cultures lost gradually the ability to form the organs as well as to develop the tissue nodules within one year of subcultures.
