Atkins am) Shkijijard — The Pigments of Fruits. 



331 



sectioas of Capsicum fruits demonstrated the presence of inhibitors in 

 them too, intense colourations being ^now produced in the pale yellow, 

 the yellow, and tlie round red varieties with both reagents ; whereas only 

 the first-mentioned gave them before. These colours were developed not 

 only in the epidermis, but in all the underlying cells. Thus it is evident 

 that the action of oxidases in the ripe fruit is largely checked by the 

 production of an inhibitor. 



Examination of over forty fruits of known pedigree has failed so far to 

 reveal any definite relation beween the oxidase reactions of parents and 

 offspring in the Fj generation. Further experiments will be made on this 

 l)oint. Surface sections of some of these fruits gave the indirect oxidase 

 (peroxidase) reaction with guaiacum tincture. Others failed to do so. But 

 too much reliance cannot be placed on these tests, as it was subsequently 

 found that the inhibitor in the deeper tissues acted as a strong reducing agent 

 and immediately decolourised the blue solution resulting from the action of 

 the surface section upon guaiacum. This reducing action was even detected 

 in one green fruit. As a rule, however, the oxidase reactions in unripe 

 fruits, both green and yellow, were rapid and intense. In the reds they 

 varied greatly, and were frequently confined to the epidermis, especially 

 when tested with a-naphthol. In the chocolate types tlie inhibitors appeared 

 to be less active than in the reds as a wliolo. Again, in the former it was 

 noticed that the cut surface, where a section had been sliced off, gradually 

 became darker till it appeared almost black. In the greens there was a 

 slight browning only, and in the reds no marked change. As a general rule, 

 however, the age of the fruit seems to be the most important factor in deciding 

 the degree of activity of the oxidase. 



