Tannin cells of persimmons 



Burton James Howard 



The fact that the tannin in persimmons becomes highly local- 

 ized during the process of ripening was pointed out by the Japa- 

 nese investigator Aso * in 1900. He calls the cells " tannin sacs/' 

 but all he mentions concerning them is that the tannin is stored 

 in large cells, and he accredits its deposition largely to the action 

 of an oxydase. He also indicates that a browning of the tannin 



mass also occurs. A still later article upon the subject is that of 

 Tichomirow,f in which certain microchemical characteristics of the 

 bodies are brought out, but apparently this author worked only 

 on ripe fruits, for none of the progressive changes during ripening 

 are noted. Because of the meagerness of some of the facts given 

 it was deemed well to look somewhat further into this phenomenon 

 in connection with chemical work being undertaken by the Bureau 

 of Chemistry, because it was thought it might shed some light on 

 some of the chemical results obtained. Cells of a form somewhat 

 similar to those present in persimmons are present in the Saint 

 John's bread {Ceratonia Siliquci) and here also serve for the depo- 

 sition of tannin. At a recent meeting of the Washington Botanical 

 Society, Mr. Walter Swingle described such cells, occuring in the 

 flesh of the date, which he termed "giant cells M because of their 



great size. 



We have chosen to call these cells tannin cells, for though in 

 some varieties they are very large, yet in others they vary only 

 little from the other parenchyma-cells in their vicinity. In the 

 persimmon the tannin cells occur in the wedge-shaped portions of 

 flesh between the carpels. They appear simply as specialized 

 parenchyma-cells, from which they differ hardly at all excepting 

 in size in the earlier stages of ripening. The shape and size of the 



* Aso : A physiological function of oxydase in Kaki-fruit. Bot. Mag. Tokyo 



14 : 179. 1900. 



f Tichomirow : Sur les inclusions intracellulars du parenchyme charnu de cer- 

 tains fruits. Compt. Rendus Acad. Sci. Paris 139 : 305. 1904. 



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