HORMONES, VITAMINS, AUXIMONES 219 



1931) grew Lemna for over thirty generations or about five months 

 on a purely mineral nutrient solution without the aid of any or- 

 ganic matter; and Wolfe (1926) and others have suggested that 

 the favorable results of Bottomley were due to the fact that he 

 started with improperly balanced solutions. The addition of the 

 organic matter merely restored this lack of balance, and the plants 

 grew better because of the improvement of the general nutrient 

 situation rather than because of any specific effect of the organic 

 matter added. Thus, even in the case of water plants, there is still 

 doubt as to their needs for "auximones." 



QUESTIONS 



1. Give the derivation of the words, auximone, hormone, and vitamin. 



2. Distinguish between hormones and vitamins; hormones and enzymes. 



3. What are the endocrine gland secretions? 



4. What structural advantages which favor hormone activity do animals 

 have over plants? 



5. Which is more nutritious, white bread or whole wheat bread? Why? 



6. Compare animals and plants in their ability to manufacture auximones, 

 hormones, and vitamins. 



7. Why do children feel the effect of a deficient diet sooner than adults? 



8. What is the difference between xenia and metaxenia? 



9. What are vitamins Bi and B 2 ? 



REFERENCES 



Appleman, C. O. — Growth promoting substances and correlation. Science, 



48:319, 1918. 

 Ashby, E. — The interaction of factors in the growth of Lemna. Ann. Bot., 



43:333, 1929. 

 Bottomley, W. — Growth of various water plants in culture solution. Ann. 



Bot., 34:353, 1920. 

 Breazeale, J. F. — Vitamin-like substances in plant nutrition. Arizona 



Agric. Exp. Sta. Tech. Bui. No. 16, 1927. 

 Budington, R. A. — Influence of ductless gland substances on growth of 



plant tissues. Woods Hole Biol. Lab. Bui., 37:188, 1919. 

 Child, C. — Certain aspects of the problem of physiological correlation. Am. 



J. Bot., 8:286, 1921. 

 Clark, N. A. — Vitamins and the world of plants. Set. Mo., 28:343, 1929. 

 Coward, K. — The formation of vitamin A in plant tissue. Biochem. J., 



17:134, 1923. 

 Funk. C. — The nomenclature of the vitamins. Science, 62:157, 1925. 

 Gericke, W. — Growth inhibiting and growth stimulating substances. Bot. 



Gaz., 78:440, 1924. 

 Heeler, V. G. — Vitamin synthesis in plants as affected by light source. 



Jour. Biol. Chem., 76:499, 1928. 



