688 J. P. Nitsch and C. Nitsch 



as vitamins, amino acids, and other chemically-defined factors. In 1942 

 tomato juice was still reported to contain an unidentified growth fac- 

 tor for hemolytic streptococci (6), and the possibility remains that 

 there are, indeed, unidentified growth factors for microorganisms in 

 tomato fruits. 



Inhibition of Seed Germination 



In any event, one of the effects of tomato juice which became 

 known first was its inhibitory effect upon seed germination. After the 

 early reports of Oppenheimer (30) and Reinhard and Gorelik (36), 

 Kockemann (11) extended this type of investigation to other fruits 

 and gave a name, blastocholine, to the principle present in the juice 

 of many fleshy fruits which inhibits the germination of seeds. Larsen 

 (14) found that the extract of ripe tomatoes contained a complex of 

 substances which were inhibitory in the Avena curvature test; he could 

 divide the ether extract into three fractions, each of which had inhib- 

 itory properties. Ozorio de Almeida et al (31), on the other hand, re- 

 ported that the factor inhibiting the germination of tomato seeds was 

 insoluble in ether or chloroform, but soluble in alcohol, whereas Sar- 

 tory and Meyer (37) found that the ether or chloroform extracts of 

 tomatoes inhibited the germination of Lepidiiim seeds. Konis (12) ob- 

 served that the inhibitory effect of tomato juice disappeared at low 

 concentrations, under which circumstances, on the contrary, a pro- 

 moting effect became visible. He thought that the inhibitor was a 

 volatile substance, which could be partially destroyed by boiling. 



Stimulation of the Growth of Immature Embryos 



Tomato juice has been reported to stimulate the growth of very 

 young embryos of Hordeurn (9). Its effect could be more or less du- 

 plicated by casein hydrolysate or sodium nucleate. Meyer (17) and 

 Vacin and Went (42) added tomato juice to media prepared for the 

 asymbiotic development of orchid seed in sterile culture, which re- 

 sulted in a marked stimulation of growth. The stimulative effect of 

 tomato juice upon immature embryos is reminiscent of that of coco- 

 nut milk (43, 44). 



Growth of Excised Ovaries 



The autoclaved aqueous extract of both green and ripe tomatoes 

 was found to stimulate the growth of excised tomato ovaries which had 

 been treated with 2-naj)luhoxyacetic acid to stimulate parthenocarpy 

 (24), as shown in Figure lA. Confirmation of these results was reported 

 with the use of a different, nonsterile technique (16). 



Growth of Roots 



Roots often form on the pedicels of tomato ovaries cultivated in 

 vitro. The tomato juice which was added to the sterile medium was 



