690 



]. P. Nitsch and C. Nitsch 



found to stimulate the development of these roots in an astonishing 

 manner. Sucrose at a concentration of 5 per cent generally inhibits 

 the elongation of adventitious roots produced on the floral peduncles, 

 as contrasted with lower concentrations which allow perfect growth of 

 the same primordia. The addition of tomato juice to the medium, 

 however, allowed roots to develop profusely, even though the sucrose 

 concentration was 5 per cent (24), as shown in Figure 1, B and C. 



Growth of Tissue Cultures 



Investigations over a period of years with various strains of tissue 

 cultures showed that tomato juice stimulated the growth of normal 

 tissues, tissues habituated to auxin, crown-gall tissues, and also tissues 

 derived from pollen or endosperm. 



Crown-gall tissues. Since crown-gall tissues are known to grow well 

 without any added auxin, no synthetic auxin was added to the media. 

 Under these conditions, De Ropp's PIII strain of crown-gall tissues 

 of Helianthus annuus and Morel's crown-gall strains of Nicotiana 

 tabacum and Opuntia monacantha (23) and Parthenocissus tricuspi- 

 data (3) all responded to the addition of tomato juice to the medium 

 by an increase in fresh weight up to five times that of the controls, for 

 the optimum concentration of 10 per cent (v/v) of TJ (Figure 2). Gau- 



CONCENTRATION [% , V/ V ) 



Fig. 2. Increase in fresh weight on addition of tomato juice to tissue cultures of 

 Morel's crown-gall strain of Nicotiana tobacum (NT) and Opuntia monacantha 

 (OM), after 5 weeks and 9 weeks, respectively. Each point represents the average of 

 6 (NT) or 10 (OM) replicates. (From 23) 



