SHORTER ARTICLES AND DISCUSSION 



INHERITANCE OF COLOR IN THE ALEURONE CELLS 

 OF MAIZE 



In those plants of which there is a considerable knowledge of 

 the heredity of flower sap color, namely, Antirrhinum, Latlnjrus. 

 Matthiola and Primula, it has been found that an hypostatic 

 color factor is often necessary for the production of an epistatic 

 color. For example, a basic factor generally designated as C 

 being present, a flower becomes red by the addition of a factor 

 R, and becomes magenta or purple by the addition of still 

 another factor P. The zygotic formula of a pure red flower is 

 RRCC and of a pure purple flower is PPRRCC; but a flower 

 with the zygotic formula PPCC is colorless. 



On the other hand, certain seed coat and other colors of wheat, 

 of beans and of other plants do not need the presence of the hypo- 

 static factor for the formation of the epistatic color. For ex- 

 ample, Nillson-Ehle crossed a black glumed oat BBGG with a 

 white glumed oat bbgg. In the F 2 he obtained 12 black : 3 gray : 

 1 white. The actual ratio was 9BG : SBg : 3bG : lbg, but as the 

 black was produced whether the gray factor was present or not, 

 the visible ratio was as given above. 



The natural conclusion is that in the first category the epis- 

 tatic factor is more specific in its action than it is in the second 

 category. If one accepts the interpretation that color is formed 

 by the action of an enzyme on a colorless chromogen, he must 

 conclude that the epistatic enzyme of the first kind can only 

 produce its action, if, by the presence of the hypostatic enzyme, 

 the chromogen has already been carried through a necessary 

 preliminary reaction. An epistatic enzyme of the second kind, 

 however, is sufficient unto itself and is absolutely independent 

 of the action of the hypostatic enzyme. One may even assume 

 that the chemical bases upon which the two enzymes of the 

 second category act are independent of one another. 



Perhaps a concrete illustration will show the difference of 

 action in these two cases better than description. In the black 

 glumed oat BBGG, one can imagine the black color or the gray 

 color wiped out mechanically. The other color remains. In the 



