22 



EFFECTS OF ARTIFICIAL SHADING ON PLANT GROWTH. 



Table VI. — Average diameter of stem at the end of 30 days, in percentages of diameter in 



normal light. 



Bed and plants. 



Section number and light intensity. 



1, n/93. 



2, n/15. 



3, n/7. 



4, n/5. 



5, n/2. 



6, n. 



Bed A (with fan): 



17 

 71 

 72 

 

 

 





 71 

 73 

 20 

 

 



28 

 82 

 91 

 17 

 60 

 33 



32 

 82 

 91 

 17 

 60 

 33 



59 

 100 

 127 



33 

 110 



73 



59 



71 

 145 



20 

 110 



91 



69 



82 

 109 



33 

 130 



62 



62 

 71 

 73 

 50 

 60 

 127 



86 

 82 

 109 

 117 

 125 

 73 



90 

 82 

 100 



42 

 115 

 127 



100 





100 



Cotton 



100 



Radish (diameter of root) 



100 



Lettuce 



100 





100 



Bed B (without fan): 



100 





100 



Cotton 



100 





100 





100 





100 







GENERAL CONDITION OF THE PLANTS AT THE END OF 50 DAYS. 



CORN. 



During the later stage of the experiment corn behaved so differ- 

 ently from the other plants that it had best be discussed separately. 

 In Table VII are shown the average green weight , the height, and 

 the diameter of stem at the end of 50 days. These measurements 

 indicate a reduction in the growth of corn even in the weakest shade. 

 With a further reduction in light, marked reduction in growth is 

 noted until in light n/93 none of the plants survived. Corn plants 

 were barely able to survive in light n/15 and in bed B failed even 

 under this illumination. 



Table VII. — Growth of corn at the end of 50 days, in percentages of growth in normal 



light. 



Bed and growth. 



Section number and light intensity. 



1, n/93. 



2, n/15. 



3, n/7. 



4, n/5. 



5, n/2. 



6, n. 



Bed A (with fan): 





 

 





 

 



35 



87 

 65 





 

 



47 

 111 

 111 



7 

 72 

 41 



84 

 87 

 71 



46 

 96 

 65 



62 

 108 

 94 



94 

 103 

 118 



100 





100 





100 



Bed B (without fan): _ 



100 





100 





100 







OTHER PLANTS. 



In Table VIII the green weights at the end of 50 days are shown. 

 An increase in weight is shown in five out of eight cases in n/7 light, 

 as compared with that in normal light. The increase is considerably 

 greater in n/5 light and still greater in n/2 light. A reduction of 



279 



