GROWTH OF ROOTS AND SHOOTS IN THE LEAF 37 



Table XII 



Dry weight 



of leaves, 



grams 



Dry weight of 

 shoots regen- 

 erated by 

 leaves, 

 gra ms 



Dry weight of 

 roots regen- 

 erated by 

 leaves, 

 grams 



Set I (with axillary shoot). . . 

 Set II (without axillary bud). 



1.745 

 1 . 754 



0.056 

 0.267 



0.027 

 0.068 



The dry weight of the two sets of leaves was about the same, 

 but that of the roots and shoots produced in the leaves them- 

 selves was considerably smaller when the axillary bud of the 

 stem was allowed to grow than when this was not the case. The 



Fig. 32. — Sister leaves, leaf to the left reduced in size. In the small piece of 

 leaf the stem inhibits the shoot and root formation completely, but in the larger 

 leaf the same mass of stem fails to inhibit regeneration completely. Apr. 13 

 to 26, 1923. 



leaves of Set I (Fig. 31), the stems of which formed axillary shoots, 

 produced in all only 83 milligrams dry weight of roots and shoots, 

 while the leaves of Set II (Fig. 31), the stems of which formed no 

 axillary shoots, produced in all 335 milligrams of roots and shoots; 

 i.e., four times as much. This difference is accounted for by the 

 weight of the 11 axillary shoots formed in the stems of Set I, 

 which was 0.454 gram. 



The inhibiting effect of a given piece of stem on regeneration 

 in the leaf must also depend on the relative size of the leaf. 



