370 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



(Vol. 10 



Summary of Literature as Regards Tissues Involved in 



Regeneration 



i 



The work on regeneration has dealt primarily with the or- 

 ganography aspect and also with the theories as to the cause of 

 the releasing stimuli in the phenomena. Some studies have laid 

 stress upon the external influences to which the plant has been 

 subjected and the relation of these to the production of regenera- 

 tive processes; likewise, the tendencies inherent in the plant 

 itself have been duly considered. Therefore, a relatively small 

 amount of literature deals with the tissues concerned in regen- 

 eration. Prantl ('74) found that in the case of corn and Vicia 

 Faba regeneration was effected through the intermediary of a 

 common callus which represented the passage of the different 

 systems into one another. Moreover, he found no differentiation 

 in the callus tissue of specific groups representing the diverse 

 tissues of the root. In 1900, and later in 1902 and 1903, Goebel 

 conducted elaborate experiments on Taraxacum, Bryophyllum 

 crenatum, and other plants. His conclusions were concerned 

 chiefly with the physiological characters of regeneration, its 

 causes and effects. Simon, in 1904 and later in 1908, after in- 

 vestigating the regeneration of root tips and shoots, stated that 

 all tissues may indirectly form a callus and then regeneration 

 may take place or, directly, each tissue may form a callus. 

 McCallum's work in 1905 on species of Phaseolus, Salix, Heli- 

 anthus, Taraxacum, and other plants was of a physiological nature, 

 dealing with the disturbances in nutrition, disturbance in water 

 content, wound stimuli, and correlation. Nemec ('05) made an 

 elaborate study of the regeneration of roots and found regenerated 

 parts developed from either a callus formation or directly from 

 the division of the cells at the base of the dermatogen. Miss 

 Kupfer ('07) found that regeneration of fleshy roots developed 

 from the cambium and callus, as in the horseradish, sweet-potato, 

 and parsnip. She makes no reference to the sectioning or pre- 

 paration of slides of her material. Therefore, from these studies, 

 organ regeneration is dependent upon the cambial and callus 

 tissues. 





