LOUIS G. NICKELL 



and 

 WALTER R. TULECKE^ 



Chas. Pfizer and Company, Inc. 



Growth. Substances and Plant Tissue Cultures 



Because of the dramatic effect obtained by applying gibberellins to 

 intact plants and the natural occurrence of at least one of these com- 

 pounds in higher plants (5), it seemed desirable to study the effect 

 of gibberellin in plant tissue culture systems where many environ- 

 mental and growth variables may be controlled, and where many of 

 the complicated influences of morphogenetic development in higher 

 plants are not present. Furthermore, the percentage of cells that are 

 meristematic (or at least nondifferentiated) is quite large compared 

 with that in intact plants. 



The present paper includes data from experiments with 49 

 strains representing 25 different species. The effects of various levels 

 of the gibberellins, variations in the media used, type of tissue, 

 source of the tissue, as well as physiological and pathological state of 

 the tissues involved, are considered. 



The main purpose of the present paper is to survey a large num- 

 ber of cultures to determine if any correlations can be made between 

 the response of tissue cultures to gibberellin and characteristics of the 

 tissues or the conditions under which they are grown, as well as to 

 compare the resultant data with those obtained from intact plants. 



MATERIALS AND METHODS 



Gibberellin 



The gibberellin used was Pfizer lot #76088, which is a mixture 

 of gibberellin A and gibberellic acid (GA). Parallel tests were run in 

 many cases with potassium gibberellate, with similar results. Solu- 

 tions were made up at 10 times the highest test level, the pH ad- 



' Subsequently: Boyce Thompson Institute for Plant Research, Inc., Yonkers, 

 N.Y. 



[675] 



