SECT. 2] ORGANIC REGULATION OF PHYTOPLANKTON FERTILITY 



Table X 

 Patterns of Specificity toward Vitamin Bi 2 -Like Compounds 



197 



Organism 



Type of nucleotide 



Benzimidazole Adenine No 



(B 12 , factor III) (pseudo Bi 2 , factor nucleotide 



A) (factor B) 



Mammals and Ochromonas 



malhamensis 

 Lactobacillus leichmannii and 



Euglena gracilis 

 Escherichia coli 



Table XI 

 B12 Specificity in Fresh -Water and Marine Algae 



strains of diatoms of the same species may require different vitamins or not 

 require them at all. This physiological variation among strains, which may also 

 occur in other algal groups, obliges us to be extremely careful in extrapolating 

 data pertaining to a strain of any species to other strains or localities. To avoid 

 gross errors one must correlate the data on vitamin content of waters, especially 

 B12, with laboratory nutritional findings obtained exclusively on species 

 isolated from the same water samples. Since this entails a great deal of work, 

 such precise analysis should be limited to the history of blooms in localities 

 where, as in Long Island Sound and off the English coast around Plymouth, the 

 succession of forms and other ecological factors have been thoroughly studied. 

 It is suspected that seaweeds or other highly differentiated algae may need 

 plant hormones for normal morphogenesis. Ulva lactuca produced the normal 

 flattening and a short leafy thallus only in nutrient sea-water ( + N, P, trace 

 metals, vitamins) enriched with adenine and kinetin (Provasoli, 1958b). 



