NO. 2 PLANT GROWTH AND WAVE-LENGTH BALANCE JOHNSTON I7 



Johnston, Earl S. 



1932. The functions of radiation in the physiology of plants. II. Some 

 effects of near infra-red radiation on plants. Smithsonian Misc. 

 Coll., vol. 87, no. 14, pp. 1-15. 

 Johnston, Earl S., and Dore, W. H. 



1929. The influence of boron on the chemical composition and growth of 

 the tomato plant. Plant Physiol., vol. 4, pp. 31-62. 

 McAlister, E. D. 



1937. Time course of photosynthesis for a higher plant. Smithsonian Misc. 

 Coll., vol. 95, no. 24, pp. I -17. 

 Popp, Henry William. 



1926. A physiological study of the effect of light of various ranges of 

 wave length on the growth of plants. Amer. Journ. Bot., vol. 13, 

 pp. 706-736 

 Roodenburg, J. W. M. 



1932. Kunstlichtcultuur. II. Over de noodzakelijke van planten en neonbe- 

 lichting bij bloemcultures. Med. Wagen. (Nederland), vol. 36, 

 no. 2, pp. 1-37. 



SCHAPPELLE, N. A. 



1929. Effect of narrow ranges of wave-lengths of radiant energy, and other 

 factors, on the reproductive growth of long-day and short-day 

 plants. Cornell Univ. Agr. Exp. Stat. Mem. 185, pp. 1-33. 

 Shirley, Hardy L. 



1929. The influence of light intensity and light quality upon the growth 

 of plants. Amer. Journ. Bot., vol. 16, pp. 354-390. 

 Steinberg, Robert A., and Garner, W. W. 



1936. Response of certain plants to length of day and temperature under 

 controlled conditions. Journ. Agr. Res., vol. 52, no. 12, pp. 943-960. 



EXPLANATION OF PLATES 

 Plate i 



Tomato plants grown for 26 days under the following intensities (watts/cm^). 

 Daily illumination was 12 hours. 



Culture Neon Mercury 



I 00023 .00002 



3 00008 .00002 



5 00005 .00007 



Plate 2 



Tomato plants grown for 21 days under the following intensities (watts/cm^). 



Daily illumination was 18 hours. 



Mazda Mercury 



Culture (water-cooled) (400 watt) 



I and 2 0404 .0013 



3 and 4 0172 .0031 



5 and 6 0065 .0067 



The darker green leaves in cultures 2, 4, and 6, due to the added (NH4)S04, 

 appear in the illustrations as a deeper shade than those in cultures i, 3, and 5. 



