36 Plant Tissue Culture 



bins independently cultivated excised root tips for 

 brief periods. 1922-1934 — The method as out- 

 lined by Kotte and Robbins was still far from 

 fully successful, and the period from 1922 to 1934 

 was again one of largely unsuccessful attempts in 

 a great many different directions. 1934—1939 — 

 In 1934 White and Gautheret gave a new impetus 

 and orientation to the subject, White by demon- 

 strating the possibility of growing isolated roots 

 for unlimited periods in vitro, Gautheret by dem- 

 onstrating the possibility of obtaining in vitro 

 growth of fragments of cambium. The period 

 1934 to 1939 was one of rapid expansion of the 

 field, of perfecting the nutrients and culture con- 

 ditions, and of gradual establishment of the tech- 

 nique on a firm basis. This was capped in 1939 

 by White's, Nobecourt's, and Gautheret 's indepen- 

 dent demonstration of the possibility of growing 

 undifferentiated tissues for unlimited periods and 

 by White's demonstration of experimental control 

 of differentiation in such cultures. 



* William J. Robbins, 1890- . Director, The New York Botanical 

 Garden, Bronx Park, New York City. Simultaneously and independently 

 from Kotte, cultivated excised root tips for the first time for limited 

 periods in artificial media. Student of the vitamin requirements of 

 plants. The author regrets that Dr. Robbins has requested that his 

 portrait be omitted from this series. 



