Jan. i9,1924 
Photoperiodtsm and Hydrogen-Ion Concentration 1 55 
day of late summer and fall a slight increase in reducing sugar was found 
in the sap of the leaf at about the time flower buds were laid down, 
followed by a decrease at the time open blossoms appeared. A marked 
increase in reducing sugar and a smaller increase in soluble nitrogen was 
observed 15 days later, when development of the fruit was rapidly 
progressing. In summer radish, elongation of the stem resulting from 
exposure to a long day is associated with an increased content of reducing 
sugar in the tissues and maximum concentration is found in the upper 
portion of the stem. 
LITERATURE CITED 
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(7) Garner, W. W., and Allard, H. A. 
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( 8 ) - 
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(9) - Bacon, C. W., and Foubert, C. L. 
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