Rothamsted Symposium on Trace Elements 60 



13. Kliman, S., 1937: The importance of ferrous iron on plants and 

 soils (Soil Sci. Soc. Am., Proc. 2:385-392). 



14. Kriel, H. T., 1941: A study of the effect of excess manganese on 

 iron and chlorophyll content and growth of tomato plants (Unpublished 

 thesis, Univ. of California, Berkeley. Ref. by Bennet, 1945). 



15. LiEBiCH, H., 1941: Quantitativ-chemische Untersuchungen iiber 

 das Eisen in den Chloroplasten und iibrigen Zellbestandteilen von Sfinacia 

 oleracea (Z. Botan. 37:129-157). 



16. Maquenne, L. and Demoussy, E., 1920: Sur la toxicite du fer et 

 les proprietes antitoxiques du cuivre vis-a-vis des sels ferreux (Compt. rend. 

 171:218-222). 



17. Neish, a. C, 1939: Studies on chloroplasts, II (Biochem. J. 

 33:300-308). 



18. Olsen, C, 1935: Iron absorption and chlorosis in green plants 

 (Compt. rend. trav. lab. Carlsberg 21:15-52). 



19. Oserkow^sky, J., 1933: Quantitative relation between chlorophyll 

 and iron in green and chlorotic pear leaves (Plant Physiol. 8:449-468). 



20. Pearse, H. L., 1944: Iron and manganese in plant nutrition 

 (Farming S. Africa 19:688-694). 



21. Rogers, C. H. and Shive, J. W., 1932: Factors affecting the dis- 

 tribution of iron in plants (Plant Physiol. 7:227-252). 



22. ScHOLZ, W., 1934: Uber die Chlorose des Leins in ihrer Bezie- 

 hung zimi Eisen und Mangan (Z. Pflanzenemahr. Diingung Bodenk. 

 34:296-311). 



23. Thorne, D. W. and Wallace, A., 1944: Some factors affecting 

 chlorosis on high lime soils, I. Ferrous and ferric iron (Soil Sci. 57:299- 

 312). 



24. Willis, L. G., 1936: Evidence of the significance of oxidation 

 reduction equilibrium in soil fertility problem (Soil Sci. Soc. Am., Proc. 

 1:291-297). 



Points from Discussion of Pafer hy Dr. Erkama 



Prof. Seekles:— 



Did you notice the pH value of the soil in the experiments on 

 the absorption of Mn, Cu and Fe in plants? fH has a very 

 considerable influence on the absorption of Mn. 



Dr. Erkama:— 



Almost all the plants here analyzed had grown in the same 

 soil. The soil was acid, and its fH varied between 4.5 and 5.4. 



Prof. Arnon:— 



In discussing the reciprocal effects of one micro-nutrient metal 

 on another two phases can be distinguished. First the effect of 



