SOME INTERRELATIONS OF COMPENSATORY 

 GROWTH, FLOWERING, AUXIN, AND 

 DAY LENGTH IN Coleus blumei Benth' 



WILLIAM P. JACOBS, ROBERT V. DAVIS, JR., 



and BOB BULLWINKEL - 



Department of Biology, Princeton University, Princeton, New Jersey 



In a previous paper, compensatory growth" of Coleus shoots and leaves 

 was described (Jacobs and Bullwinkel, 1953). Excising the axillary 

 buds and branches induced compensatory growth in the main shoot; 

 and excising, in addition, some of the leaves on the main shoot resulted 

 in still further compensatory growth of the leaves that remained. Evi- 

 dence was presented in support of the interpretations (1) that the 

 compensatory growth of the main shoot was mainly due to greater 

 growth of the young leaves on the main shoot; (2) that this compen- 

 satory growth of the young leaves, in turn, caused greater growth of 

 the young internodes. When synthetic auxin in the form of indoleacetic 

 acid (lAA) was substituted for the axillaries, the results were not 

 absolutely clear-cut: the auxin-treated plants were typically inter- 

 mediate between the untreated controls and the "axillaries-off" plants, 

 although closer to the latter. 



This paper investigates further the report in the previous paper that 

 excising axillary buds and branches resulted in faster flowering as well 



1 Research supported by grants from the National Science Foundation and 

 American Cancer Society and by funds of the Eugene Higgins Trust allocated 

 to Princeton University. The aid of Dr. Roy Sachs, Miss L B. Morrow^, and Mrs. 

 R. Speagle is gratefully acknowledged. 



- The contributions of the junior authors were incorporated in their Princeton 

 College Senior Theses (1955 and 1952, respectively). 



2 Compensatory growth was defined as the special type of regeneration charac- 

 terized by greater than normal growth of an organ or organs of the same type 

 as the one which has been lost. Regeneration was defined as the totality of 

 phenomena of growth and differentiation which results from loss of a part of a 

 living organism. 



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