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CHIMERAS IN GRAINS OF MAIZE. 



Three grains of maize showing chimeras in which the endosperm characters sugary and 



starchy are involved. (Fig. 5a, b, c.) 



A color chimera in an F2 grain of sweet maize. (Fig. 5d.) 



of the leaves growing on the tree which 

 produced the fig-chimera were charac- 

 terized by white areas or sections, as 

 shown in Fig. 4. Many examples of 

 this kind of chimera have been demon- 

 strated. Norton was able to trace a 

 foliage color difference down the stalk 

 as a different colored stripe in a whole 

 branch of a tomato plant, narrowina: 

 until its origin was apparently located 

 in a single cell. Buds pushing out at 

 the point of union between the stripe 

 and the normal colored portion of the 

 stem bore two-colored leaves similar to 

 the fig leaf in Fig. 4. 



If we use the mutation hypothesis to 

 account for a change in color in a por- 

 tion of a corn grain, it would appear 

 reasonable to expect that mutations 

 might occur in factors affecting other 

 chemical constituents of the endosperm. 

 Grains of corn showing such changes 



in endosperm have been found^ (Fig- 

 5a, b, c) among the hybrid progeny of 

 two other different strains. The cross 

 between the varieties Countr}^ Gentle- 

 man (sweet) with U. S. White Dent 

 (starchy) produced among the F, prog- 

 eny seven grains with sweet patches 

 in the starchy endosperm (Fig. 5a,b,c). 

 Among the F, grains derived from 

 the one shown in Fig. la, a half purple 

 and half white sweet grain was found, 

 to which a great deal of interest is 

 attached, because in this grain lies the 

 possibility of our being furnished with 

 the proof that the mutation hypothesis 

 here given is the correct one. If the 

 progeny from this grain (Fig. 5d) gives 

 evidence that the embryo is homozygous 

 for the purple color, then the change 

 from purple to white in the aleurone 

 can only have come about by somatic 

 mutation in the manner herein de- 



Furnished by Dr. R. E. Clausen. 

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