Bitter Pit in Apples. 411 



no signs of solution. In Five Crowns there are rarely more 

 than to 6 such cells in a preparation 1 cm. diameter, and 

 1 to three cells thick, whereas in Jonathans there may be from 

 to 50 such cells present in the same amount of sound, living 

 pulp. These cells show no other signs of injury or death, their 

 protoplasm appeared to be living, and when tested on carefully 

 made preparations Avas plasmolysable. A sound, ripe Jonathan 

 apple, free of all external signs of bitter pit, may. therefore, con- 

 tain some thousands of living but starch-bearing cells. So far 

 as the apples examined were concerned, the non-solution of the 

 starch grains in occasional scattered pulp cells is not an abnor- 

 mal but a normal phenomenon. 



The non-solution of the starch grains. 



The question at once arises. Why do the starch grains in occa- 

 sional cells of otherwise sound apples and in numerous cells in 

 ordinary bitter pit tissue, remain undissolved during ripening? 



In the first place it must be noted that natural bitter pit is 

 not accompanied by cells with undissolved starch grains if it 

 appears or is produced in young apples before the starch grains 

 have appeared in the general pulp. Such apples usually fall 

 off without ripening, probably as the result of excessive poison- 

 ingi. Secondly, when it develops late after storage, there may 

 be no more starch grains in the dead tissue than in the general 

 pulp. Thus Jonathan, Sturmer Pippin and Scarlet Nonpareil 

 apples, which had been heavily sprayed during development, 

 were picked over, and all bitter pit apples removed. An abun- 

 dance of starch grains was present in the bitter pit tissue in 

 every case. The sound apples were kept in cool storage for four 

 months. Many of them developed large, deep bitter pits, almost 

 every one of which was beneath a breathing pore. Occasional 

 starch containing cells were present in the dead tissue, but not 

 perceptibly more than in the healthy pulp tissue. 



The non-solution of starch grains in living pulp cells can only 

 be due to the following factors : — (1) the diastase ferment which 



1 This may be the reason for the fact that so many young- fertilized apples often fall 

 from apple trees for no apparent adequate rea«(on. 



15a 



