340 Mineral Nutrition of Plants 



and will continue to provide in the future, a scientific basis for fertili- 

 zation practices. As the list of essential elements has expanded, it was 

 possible to answer with increasing assurance how many indispensable 

 nutrients need to be supplied in the external medium to insure optimal 

 plant growth. It is hoped that advances in our knowledge of the func- 

 tion of inorganic nutrients will provide a sound basis for estimating 

 quantitative requirements of fertilizer elements for different crops at 

 different stages of growth and in relation to climatic factors. 



REFERENCES 



i. Arnon, D. I., Soil Sci., 44:91 (1937). 



2. , Am. }. Botany, 25:322 (1938). 



3. , Science, 92:264 (1940). 



4. , Plant Physiol., 24:1 (1949). 



5. , and Hoagland, D. R., Science, 89:512 (1939). 



6. , and Hoagland, D. R., Soil Sci., 50:463 (1940). 



7. , and Meagher, W. R., Soil Sci., 64:213 (1947). 



8. , Simms, Helen D., and Morgan, Agnes Fay, Soil Sci., 63:129 



(i947)- 



9. , and Stout, P. R., Plant Physiol., 14:371 (1939). 



10. , and Stout, P. R., Plant Physiol., 14:599 (1939)- 



11. , and Whatley, F. R., Arch. Biochem., 23:141 (1949). 



12. , and Whatley, F. R., Unpublished data (1949). 



13. Becker, D. E., Smith, S. E., and Loosli, J. K., Science, 110:71 (1949). 



14. Berger, L., Stein, M. W., Colowick, S. P., and Cori, C. F., /. Gen. 

 Physiol., 29:379 (1946). 



15. Bertrand, G., Compt. rend., 124:1032, 1355 (1897). 



16. Bradfield, J. R. G., Nature, 159:467 (1947). 



17. Chandler, W. H., Botan. Gaz., 98:625 (1937). 



18. Folley, S. J., and Greenbaum, A. L., Biochem. ]., 43:537 (1948). 



19. Hewitt, E. }., and Jones, E. W., /. Pomol. Hort. Sci., 23:254 (1947). 



20. Hill, R., Proc. Roy. Soc. (London), 1276:192 (1939). 



21. Hoagland, D. R., Proc. Am. Soc. Hort. Sci., 38:8 (1941). 



22. , Lectures on the inorganic nutrition of plants (Chronica Bo- 



tanica, 1944). 



23. , and Snyder, N. C, Proc. Am. Soc. Hort. Sci., 30:288 (1933). 



24. Holt, A. S., and French, C. S., in J. Franck and W. E. Loomis, 

 Editors, Photosynthesis in Plants (Ames, Iowa: Iowa State College 

 Press, 1949), chapter 14. 



25. Horner, K. C, Burk, D., Allison, F. E., and Sherman, M. S., /. Agr. 

 Research, 65:173 (1942). 



