Xne Ohio Journal of Science 



Vol. XXI JANUARY, 1921 No. 3 



SEASONAL CHANGES AND TRANSLOCATION OF 



CARBOHYDRATE MATERIALS IN FRUIT SPURS 



AND TWO-YEAR-OLD SEEDLINGS OF APPLE.*! 



SWARXA KUMER MiTRA. 



Laboratory of Plant Physiology, Ohio State University. 



At the suggestion of Prof. W. Paddock, of the Department 

 of Horticulture of the Ohio State University, the writer under- 

 took the work of determining the changes in carbohydrate 

 content of fruit spurs and two-year-old seedlings of apple 

 throughout the year. The work was done under the direction 

 of Dr. H. C. Sampson, of the Department of Botny, and with 

 the assistance of Dr. T. G. Phillips and Dr. J. F. Lyman, of the 

 Department of Agricultural Chemistry. 



This is a part of the larger problem of determining what 

 effect the carbohydrate content of fruit spurs has upon vege- 

 tative growth and reproduction, and to what extent it should be 

 considered in handling fruit trees. 



The methods used in the analysis of plant materials were as 

 follows: The samples were collected from the campus orchard 

 and nursery every two weeks and a quantitative analysis was 

 made in every case to determine the percentage of starch and 

 the sugars, sucrose, glucose, and maltose. For the determina- 

 tion of starch the method described by Abderhalden^ was 

 followed, and for sugars, that described by Darwin and Acton^ 

 with a slight modification. In both cases the quantity of 

 dextrose was determined by Fehling's solution, titrating against 

 a standard potassium permanganate solution, as has been 

 approved by the Association of Official Agricultural Chemists.^ 

 In the case of two-year-old seedl ngs, separate analyses were 

 made on the one-year-old stem segments, two-year-old stem 

 segments, and roots. All percentages are expressed on a dry 

 weight basis. 



*Paper read at the Thirtieth Annual Meeting of the Ohio Academy of Science, 

 May 15, 1920, Columbus, Ohio. 



fPapers from the Department of Botany, Onio State University, No. 121. 



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