30 
I. N AG Al: 
a. Brown when fully mature. 
b. Faint yellow when fully mature. 
The brown and faint yellow awns are green when young and the 
alcoholic extract of the green material of the brown awn yields a distinct red 
colour by reduction but that of the faint yellow, only a slightly red tinge. 
If oxidase is added to the extract, a marked brown colour is produced in the 
former, while in the latter, practically none. It proves that the colour of the brown 
awn is due to the pigment produced by the oxidation of the cliromogenic 
substance at the end of the growing period of the plant. The extract of the 
matured brown awn gives also a distinct reduction colour showing that a 
part of the chromogenic substance remains without undergoing any .serious 
change. In the matured awn, the brownish yellow substance, sometimes in 
aggregates, fills the cell, and when treated with ammonia, yields a deep yellow 
colour. The relative strength of the chromogen content of certain varieties 
are given below. 
Table 14. 
Chromogen content of the extract of immature green awn of Oryza sativa. 
Name of variety 
Colour when mature. 
Chromogen 
P F 
Oxidation colour 1 
“ Sekiyama ” 
Brown 
— 
II 
Brown 
“ Uhei ” 
11 
— 
II- 
“ Kura-fusagi ” 
11 
— 
IV 
91 
“ Meirinsen ” 
11 
— 
III 
11 
“ Daijo-slnro ” 
Faint yellow 
— 
VI 
“ Chujo ” 
?» 
— 
V 
“ Koshin-den ” 
?» 
— • 
V 
Pale yellow 
“ Yamato-chikara ” 
91 
— 
VI + 
“ Tanpo ” 
11 
— 
V+ 
“ Shirahige ” 
„ 
— 
VI 
11 
“ Nagoya-shiro ” 
91 
— 
VI 
19 
Unlike the awn, the leaf does not vary very widely in the chromogen 
content. The result of the tests made over 120 varieties at the middle of 
August, 1919, is given in Table 15. 
1. Pressed sap of the radish root and hydrogen peroxide is added. 
