STARCH IN APPLE TREES. 



W. A. Price. 



In the absence of reliable data and abundant literature upon 

 the subject of starch storage and its changes throughout the 

 year, I have undertaken experiments which I hope will shed 

 further light upon the problem. The changes in the living 

 tissues, the sap wood and particularly the bark, were found 

 unexpectedly complicated. A few of the typical conditions 

 may be given for which an explanation is not as yet attempted. 

 The presence of starch in the non-living tissue, the heart wood, 

 was studied in detail, believing the conditions found may have 

 an important bearing in explaining the very ready decay of 

 apple tree wood, in comparison with that of some other trees. 



In case of the living tissue, sections about 20 mic. in thickness 

 were made at intervals of ten days in dormant season, and four 

 or five days during the growing season. The presence of starch 

 was determined, in the usual way, by the iodin test. Each 

 time, one-year old, or older, twigs were examined, both from 

 the higher and lower portions of the crown of the tree; and 

 beginning April 17th, the roots were examined. 



This work was done at Ohio State University in the spring 

 of 1914, under the general direction of Prof. Wendell Paddock, 

 head of the Horticulture Department, and Mr. Forest B. H. 

 Brown of the Botany Department. 



The following typical conditions were found: 



-f- = starch present. = starch absent. 



May 14, clear; March 9, partly cloudy; other dates, cloudy. 



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