TABLES 



No 



Page 



1 Composition of macrophyte nutrient medium 10 



2 Yield of and total nitrogen concentration in 

 index segments of Elodea grown in solutions 

 differing in nitrogen content 14 



3 Total nitrogen concentration in nitrogen- 

 deficient Elodea segments 17 



4 Yield and total phosphorus concentration in 

 index segments of Elodea grown at various 

 phosphorus concentrations 19 



5 Phosphorus concentration in phosphorus-deficient 

 Elodea segments 20 



6 Critical concentrations of essential elements 



in index segments of Elodea 21 



7 Critical concentrations of essential elements 



in index segments of Ceratophyllum 22 



8 Essential element concentrations in Elodea 



from Little John Lake 28 



9 Essential element concentrations in Elodea 



from Salsich Lake 29 



10 Concentrations of growth-limiting elements in 

 Elodea from Wisconsin lakes sampled in late 

 July 32 



um 



11 Essential element concentrations in Ceratophyll 

 from Lake Mendota " 33 



12 Nitrogen and phosphorus concentrations in 

 macrophytes from nutrient assay baskets 35 



13 Nutrient solution recommended for macrophyte 

 culture 41 



14 Toxicity of copper to Ceratophyllum 43 



Vll 



