36 



REGENERATION 



Large numbers of pieces of stem, about 25 millimeters long, each 

 with 1 node and possessing 2 leaves, were cut out and the pieces 

 of stem were split longitudinally as nearly in the middle of the 

 stem as possible (Fig. 31), so that each sister leaf was connected 

 with half a piece of stem. In one set of leaves the axillary bud 

 of the stem was removed (II, Fig. 31), while in the set of sister 

 leaves the axillary bud was left intact (I, Fig. 31). The leaves 

 of both sets were suspended in an aquarium, dipping with their 

 apices into water. The axillary buds grew out in 1 1 of the half 

 stems with leaves attached, and these 11 specimens and their sister 

 leaves connected with half stems the axillary buds of which were 



Fig. 31. — The inhibitory action of a piece of stem on root and shoot forma- 

 tion in leaf is greater when the axillary shoot can grow out as in I than in sister 

 leaf II where the axillary bud of the stem was removed. Mar. 13 to Apr. 9. 



removed, were selected for a quantitative measurement of the 

 influence of the growth of the axillary bud on the regeneration in 

 the leaf (Fig. 31). It was found that the leaves connected with 

 the pieces of half stem, the axillary bud of which was cut out, 

 produced a greater mass of shoots and roots than the sister leaves 

 connected with the other piece of stem, the axillary bud of which 

 was allowed to grow. This latter bud attracted and consumed a 

 good deal of the material which in the sister leaves was available 

 for regeneration in the leaves themselves. The experiment 

 lasted from Mar. 13 to Apr. 9, 1923. Table XII gives the 

 quantitative results. 



