MANGANESE 267 



plants grown in nutrient solution (Mn-7). About 35 fxc Mir''-' was used 

 in each culture solution, and the level of manganese was varied from 0.") 

 to 50 ppm. For radioassay, the plant tissue was dried at 105°C, then 

 finely ground, and spread evenly over an aluminum pan for measurement 

 with a Geiger tube. Autoradiograms were made using Kodirex no-screen 

 X-ray film. The tissue was first pressed flat and then placed on the film 

 in the dark; with fresh material, the film and tissue were separated by 

 cellophane. The film and sample were pressed between two glass plates 

 and exposed for 6 to 12 days at refrigerator temperatures. 



Mn" was employed to study absorption and distril)ution in plants, the 

 fate of manganese applied to the soil, and the effects of various trace 

 elements on manganese behavior in the soil-plant system (Mn-8). Seed- 

 lings were grown for 3 weeks in standard nutrient solution in 4-gal solu- 

 tion jars, to which was added 5 nc Mn^^ per week. In pot studies about 

 30 /xc INIn^^ was used per 7 lb of air-dry soil. Plant tissue was assayed by 

 ashing 0.3-g samples in a metal planchet at 500°C and counting directly 

 with an end-window tube. Soil was treated with HNOs and HCIO4 to 

 destroy organic matter, and the sample concentrated to a definite volume. 

 Aliquots were pipetted into a pyrex glass planchet, the inside walls and 

 top edges of which were coated with silicone grease to prevent creeping. 

 The solution was evaporated to dryness for counting. For autoradio- 

 grams, leaves were dried in a botanical press and placed in direct contact 

 with no-screen X-ray film. 



Mn-1. Fore, H., and R. A. Morton: Microdetermination of Manganese in Biological 

 Material by a Modified Catalytic Method, Biochem. J. London, 51: 594-598 

 (1952). 



Mn-2. Charney, Jesse, and W. P. Fisher: A Microbiological Assay Method for Micro- 

 gram Quantities of Manganese in Biological Material, Science, 114: 687-688 

 (1951). 



Mn-3. Burnett, William T., Jr., Robert R. Bigelow, Allyn W. Kimball, and Charles 

 W. Sheppard: Radiomanganese Studies on the Mouse, Rat and Pancreatic 

 Fistula Dog, Am. J. Physiol., 168: 620-625 (1952). 



Mn-4. Greenberg, David M., and W. Wesley Campbell: Studies in Mineral Metab- 

 olism with the Aid of Induced Radioactive Isotopes. IV. Manganese, Proc. 

 Natl. Acad. Sci. U.S., 26: 448-452 (1940). 



Mn-5. Mohamed, Mustafa Safwat, and David M. Greenberg: A Tracer Study witli 

 ^Xln*" on Chicks with Perosis Produced by a Synthetic Manganese Deficient 

 Diet, Proc. Soc. Exptl. Biol. Med., 54: 197-200 (1943). 



Mn-6. Bowen, Vaughan T. : Manganese Metabolism of Social Vespidae, J. Exptl. 

 Zool., 115: 175 205 (1950). 



Mn-7. Millikan, C. R. : Radio-autographs of Manganese in Plants, Atislralian ./. 

 Sci. Research, 4: 28-41 (1951). 



Mn-8. Romney, Evan M., and Stephen J. Totii: Plant and Soil Studies with Radio- 

 active Manganese, Soil Set., 77; 107-117 (1954), 



