[Development of root-layers of symphytum officinale L. and their storage and consumption of carbohydrates].

In root-layers of Symphytum officinale development as well as storage and consumption of carbohydrates is determined by day length, in a manner similar to that in plants developed from seeds. Root-layers differ in the following points: 1. Flowers are always formed after 16-19 leaves, even at a day length of 12 hours at which 26-29 leaves usually appear before flowers are formed. 2. In cultures kept at temperatures of at least +10° C fructosans are stored in the young shoot-born roots, while the amount of fructosans is reduced in the buds, in the subterraneous shoot parts and in the old root pieces. The old root piece remains a living part in the root-system of the layer and takes part in the renewed storage of starch just like the primary root of plants developed from seeds.