692 J. P. Nitsch and C. Nitsch 



strains of habituated Scorzonera Jiispanica (Figure 3) and of iiabituat- 

 ed Parthenocissus tricuspidata (25). 



Normal tissues. Normal tissues, such as those of Morel's normal 

 strain of Parthenocissus tricuspidata (3) and the tuber tissues of Heli- 

 anthus tuberosus (24) responded to TJ by a clear-cut increase in 

 growth, providing a synthetic auxin was added to the medium (Figure 

 4). Tissues from roots of Scorzonera hispanica, from tubers of Solanum 

 tuberosum or from fruit parenchyma of apples did not grow on 

 media containing TJ plus a synthetic auxin. 



Special tissues. LaRue (15) mentions tomato juice among other 

 addenda tried in order to stimulate the proliferation of endosperm 

 tissue in sterile culture, and Tulecke (41) used tomato juice in some 

 of his cultures of Ginkgo pollen, which led to the formation of un- 

 differentiated masses of tissue. 



Induction of Bud Formation 



Cultures of Gautheret's habituated strain of Scorzonera hispanica 

 occasionally formed small buds when cidtured on 5 per cent TJ. These 

 buds could be made to develop until 1 or 2 small leaf primordia be- 

 came visible. Later on, however, the buds died.- 



The effects which have been listed here are varied, and they may 

 well be due to different constituents of the tomato juice. We will re- 

 strict ourselves, therefore, to that effect which more specifically 

 stimulates growth by increase in fresh weight in undifferentiated tis- 

 sue cultures. 



GENERAL PHYSIOLOGICAL PROPERTIES OF 

 TOMATO JUICE 



Looking for an explanation for the stimulative effect observed in 

 tissue cultures, we have come to the following conclusions: 



Active Principle in TJ Not an Auxin 



Added auxins have no stimidatory effects on crown-gall cultures 

 (10), in contrast to TJ. Moreover, to obtain a stimidation of growth 

 with TJ on normal and certain other strains of tissue cidtines, an 

 auxin must be added to the medium (25). 



"Using Skoog's technique, it lias since been found that a purified fraction of 

 the tomato juice which, alone, had no growth-promoting properties on tobacco pith 

 tissue, produced a voluminous and healthy callus when combined with 1 mg/1 of 

 lAA. This is exactly what kinctin did to the same tissue. After some 6 weeks, manv 

 buds developed on the growing cultures, just as they developed on cultures grown 

 on kinetin plus lAA. It can be concluded, therefore, that TJ contains a natural 

 kinin. [Sec Nitsch, J. P. Presence dime substance du type "cineline" dans Ic jus dc 

 tomates. Bui. Soc. Bot. France. 107. 1960. (In press.)] 



