Table 2. The total nitrogen content of the first and second 

 one-inch sections of stems and branches of Elodea 

 occidentalis after culturing in solutions 

 differing in nitrogen content to establish the 

 critical nitrogen concentration in an index 

 segment. 



N content 

 of medium 

 (mg/1) 



Oven-dry plant wt. Tissue N content 

 (g/2 1) (%) 



Plant 

 Ave. segment 1 2 Ave, 



10.5 1.583 1.575 1.579 1st 1" 1.45 1.49 1.47 



2nd 1" 1.14 1.15 1.14 



3rd 1" 1.07 1.09 1.08 



14.0 1.694 1.928 1.833 1st 1" 2.04 1.75 1.89 



2nd 1" 1.52 1.35 1.43 



3rd 1" 1.37 1.09 1.23 



21.0 2.428 2.252 2.340 1st 1" 2.13 2.05 2.09 



2nd 1" 1.63 1.55 1.59 



3rd 1" 1.36 1.41 1.39 



31.5 1.933 2.371 2.152 1st 1" 4.10 3.21 3.67 



2nd 1" 3.19 2.45 2.82 



3rd 1" 2.54 2.07 2.31 



42.0 1.861 1.931 1.896 1st 1" 5.56 5.35 5.45 



2nd 1" 4.38 4.26 4.32 



3rd 1" 3.45 3.31 3.38 



14 



