The History of Plant Tissue Culture 31 



basis for the continued study of the subject of 

 "plant tissue cultures." 



Haberlandt's influence, while tending to orient 

 the subject in a fundamentally unfruitful direction, 

 nevertheless did keep interest in the field alive. 

 Moreover, Haberlandt was a sound enough scien- 

 tist to see that there were other possible orienta- 

 tions and to encourage them even though he did 

 not recognize their full value. In 1922 one of his 

 students, Kotte, 51, 52, (Fig. 10) made the first 

 important experimental contribution to the sub- 

 ject. Kotte chose to work not with single, green, 

 mature cells, but with colorless meristems, excised 

 root tips. His motivation in this choice, although 

 not very clearly formulated, appears to have been 

 similar to that which oriented the present writer's 

 choice of material a decade later (White, 1931, 32, 

 1932, 89), namely, their meristematic character, 

 their ease of excision and consequent relative 

 freedom from trauma, and the considerable 

 variety of their normal physiological responses. 

 Kotte succeeded in cultivating excised root tips 

 of pea and maize in a variety of nutrients. These 

 all contained the salts of a dilute Knop solution. 

 To these were added various combinations of glu- 

 cose, peptone, asparagin, alanine, glycine, Liebig's 

 meat extract, a pepsin-diastase digest of pea 

 seeds, etc. The most satisfactory results, in 



