THE VALIDITY OF THE MASS RELATION 



51 



Experiment I.— Oct. 25, 1921, to Nov. 25, 1921 



Dry Weight 



or Shoots 



Grams per Gram 



OF Stem, 



Milligrams 



Six long pieces with six nodes each. 



Dry weight of stems 9 . 260 



Dry weight of 13 shoots 0.260 28.0 



Dry weight of roots . 057 



Control. Seven short basal pieces with one node each. 



Dry weight of stems 2 . 895 



Dry weight of 13 shoots 0.088 30.4 



Dry weight of roots . 003 



It is apparent that the basal control pieces produced approxi- 

 mately the same amount of shoots per gram of stem, namely 

 30.4 milligrams as compared with 28.0 for the large pieces. 



Experiment II.— Nov. 2, 1921, to Dec. 6, 1921 



Dry Weight 

 OF Shoots 

 Grams per Gram 



of Stem, 

 Milligrams 



Five long pieces of stem with six nodes each. 



Dry weight of stems 6 . 486 



Dry weight of 10 shoots 0.272 42.0 



Dry weight of roots . 0458 



Control. Four short basal pieces with one node each. 



Dry weight of stems 1 . 058 



Dry weight of 8 shoots 0.041 39.0 



Dry weight of roots . 0034 



Again the short basal control pieces produce about as much 

 shoot material per gram (39 milligrams), as the large pieces 

 (43 milligrams). 



Experiment III.— Nov. 16, 1921, to Dec. 20, 1921 



Drv Weight 

 OF Shoots 

 Grams per Gram 



OF Stem, 

 Milligrams 



Nine long pieces of stem with six nodes each. 



Dry weight of stems 18.658 



Dry weight of 26 shoots 0.944 50.3 



Dry weight of roots 0. 1428 



Control. Eighteen small basal pieces of two nodes each. 



Dry weight of stems 18 . 147 



Dry weight of 36 shoots 0.800 44.0 



Dry weight of roots . 136 



