THE INHIBITORY ACTION OF APICAL LEAVES 



97 



the stem) is removed, and if also the bud opposite the leaf is 

 removed (Fig. 74), one of the two buds for shoot formation in the 

 first node below the leaf can grow out, namely the one on the side 

 where the half of the base of the petiole is removed. In this 

 case the path of the descending sap from the leaf goes through 

 only one of the two buds in the first node below the leaf and in 

 this alone the shoot formation is inhibited. 



Fig. 73. Fig. 74. 



Fig. 73. — Young stem with only a small piece of one leaf at apex. In this 

 case the shoot formation in the node below the leaf is no longer suppressed. 

 (Bud opposite leaf in node is cut out.) 



Fig. 74. — Half of the base of the petiole of leaf cut out. In this case one of 

 the two buds in the first node below the leaf can grow out; namely, on that 

 side where the base of the petiole of the leaf is removed. (Bud opposite leaf 

 in node is cut out.) 



The question arose whether basal leaves can overcome the 

 inhibiting effect of apical leaves on the regeneration of the stem. 

 This is possible when there is only one leaf at the apex but not 

 when there are two. Thus a stem with a pair of leaves in the 



