59 Erkama: Copper, Manganese and Iron 



almost exclusively in phloem, the copper being transferred, from 

 cell to cell, by an exchange between surfaces (10). If we con- 

 sider that copper in protoplasm, as well as in the soil, oxidizes 

 iron to an insoluble ferric state, copper, we may say, eliminates fer- 

 rous iron from water solution. 



Manganese, which is assumed, for a good part, to enter and 

 to move in solution, catalyzes, according to Chapman (2) and 

 Pearse (20), the oxidation of ferrous iron to insoluble ferric 

 compounds in vacuolar sap and tracheids. This results in a lack 

 of iron in protoplasm. Consequently, manganese has the same 

 eJ0Fect on iron in vacuolar sap as copper in protoplasm. Copper 

 in plants results in iron deficiency in plant sap as well as in an 

 iron excess in the protoplasm. Manganese in plants, on the 

 contrary, causes an excess of ferric iron in plant sap and an iron 

 deficiency in the protoplasm. 



References 



1. Bennet, J. P., 1945: Iron in leaves (Soil Sci. 60:91-105). 



2. Chapman, G. W., 1931: The relation of iron and manganese to 

 chlorosis in plants (New Phytologist 30:266-283). 



3. Chapman, H. D., Liebig, G. F. and Vanselow, A. P., 1939: 

 Some nutritional relationship as revealed by a study of mineral deficiency 

 and excess symptoms on citrus (SoU Sci. Soc. Am., Proc. 4:196-200). 



4. Delf, E. M., 1946: Translocation of copper in plants (Nature 

 157:666-668). 



5. Densch, a. and Hunntus, T., 1924: Versuche mit Kupfersulfat 

 (Z. Pflanzenernahr. Diingung A 3:369-386). 



6. Erkama, J., 1947: Ober die Rolle von Kupfer und Mangan im 

 Leben der hoheren Pflanzen (Ann. Acad. Sci. Fennicae A II, 25:1-105). 



7. Fischer, F. G. and Hultzsch, K., 1938: Ober die Bindung des 

 Eisens in Eiweisstoffen (Biochem. Z. 299:104-122). 



8. Hopkins, E. F., 1930: The necessity and function of manganese 

 in the growth of Chorella sp. (Science 72:609-610). 



9. Jacobson, G., 1945: Iron in the leaves and chloroplasts of some 

 plants in relation to their chlorophyll content (Plant Physiol. 20:233-245). 



10. Jenny, H. and Overstreet, R., 1939: Surface migration of ions 

 and contact exchange (J. Phys. Chem. 43:1185-1186). 



11. Johnson, M. O., 1917: Manganese as cause of the depression of 

 the assimilation of iron by pineapple plants (J. Ind. Eng. Chem. 9:47-49). 



12. Kisser, J. and Lettmayr, K., 1934: Untersuchungen iiber die 

 Auswaschbarkeit der von Samen absorbierten Sake und ihre Bedeutung 

 fiir die Samenstimulation (Z. Pflanzenernahr. Diingung A 34:172-181). 



