A GE>'ETICO-rHYSIOLOGrCAL STUDY ON THE FOUMATIOX ETC. 



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11 ^'oiip i)f snbsttuices such ius nincluriii, ltit«()liii, oatechin, quercetiu niid 

 scopiiriii, also m-lds protocatecliuic add ami plüurogluciu as their deooiu|y«i- 

 tiou producta. So ho sup|x)sed that those pMobapheues which _>-iol(l ])rotoc'ate- 

 chuii- acid aud pMoroghicin are the derivatives of the substance just mentioued. 

 In the epidoruus of leaves aud the psripheiy of the bark, those substances may 

 imdergo oxidation by the contact \\ith air resulting in the formation of 

 phU)bapheno. 



^\\vLXEii (1890)" studied thu sklorotie tissue c>f the rhizome of fenis aud 

 came to the conclusion tliat the brown pigment deposited in the membrane 

 is idcnticjJ with plilobapheue and its physiological function was considered l)y 

 him to be the protection of the tissue fi-om the injm-ious eflfect of the humidity 

 of the substi'ate under which these plants gi'o^v. 



Some of the brown pigments found in natm-e are hardly soluble iu common 

 organic solvents like ether, alcohol, benzine, aud acetic ether, but are readih' 

 soluble iu water and especially in alkaline solutions, >-ieldiug a deep browuisli 

 red to wine red colom*, which In- acid is iustautlj' changed to yellow. The 

 bro\vn and reddish brown oxidation products of flavoues and flavonols as akeady 

 stated iu the preceding chapter, possess similar properties. Since the flavoue 

 derivatives ai"e widely disfciibuted in plants, it seems quite probable to assume 

 that some of them give rise to phlobapheue Ijy oxidation as Hlasiwetz has 

 alresid_y supposed. Therefore, we may regard certain flavone and flavouol 

 deri^•atives as the chromogeu of both authocvanin aud phloljaphene pigments. 



We assume that certain relatioas existing among these pigments may 1« 

 B Dine what as follows : 



1. ■\Valtek, G., Ueber die braunwandigen sklerotischen Gewebeelemente der Fame, mit 

 Ijesonderer Ucriicksichtigimg der sog. " Stützbündel " Eussow's. Bibüotheca Botanica. Heft 

 18:21, 1890. 



2. See SmBATA, K., Shibata, Y. and Kashiwagi, I., Studies on .Inthocyanins. Color Vari.a- 

 tion in Anthocyanins. Joiir, Amer. Chem. Soc. 41 : 208, lül!). 



