210 Albinism in Maize 



turn greenish or green the studies indicate that the gradual develop- 

 ment from small and comparatively few granular bodies into apjwrently 

 normal plastids is synchronous with the changing of the plants from 

 the yellowish-white condition of the young seedlings to the green 

 condition of the older plants. 



This condition differs from that in plants which are yellowish-white 

 because of being grown in darkness. Seed which was known to produce 

 only normal green plants was j^lanted in a flat and was germinated in 

 the dark. The young seedlings were yellowish in colour (no green 

 showing), and preparations of the leaves showed that plastids were in 

 abundance (Fig. 6). 



Fig. 6. Cross section through a leaf of a 

 seedling made yellowish by being germi- 

 nated and grown in darkness, x 380. 



The leaves of the race of maize known as Zea jrqyonica have stripes 

 of dark green, pale green, and white ( PI. VIII, fig. 86). In the dark-green 

 area of these leaves chloroplasts are present in approximately the same 

 number, and are about the same size as in ordinary green leaves (Fig. 7), 

 while in the white portion there are very few, if any, plastids. There 

 were noted, however, a very few small bodies which may have been 

 leucoplasts. The pale-green stripe afforded an interesting study. 

 Fig. 8 shows the position of the plastids which are present. They 

 are seen to be in only those cells next to the lower epidermis. Since 

 this is the case, the intensity of the green colour is diminished as the 



