and Golden Delicious apples. In Delicious apples 20 percent of the 

 skin segments showed russet and in Golden Delicious, 80 percent; 

 after 7 months' storage 3 percent of the Delicious and 80 percent of 

 the Golden Delicious were shriveled. These findings confirm and 

 extend those reported by Pieniazek (34) • 



Delicious and Rome Beauty, the varieties that showed the best 

 keeping quality, had the smoothest, most homogeneous, and least 

 interrupted cuticle; Delicious also contained the best developed cutin 

 deposits between and below the epidermal cells. Although Golden 

 Delicious contained almost as much supplementary cutin as Delicious 

 apples, the broken, channeled, eroded, and porous cuticle contributed 

 to this variety's poor storage quality. The cuticle of Stayman apples 

 also was broken, channeled, eroded, and porous, but slightly thicker 

 than that of the other varieties. The cuticle of Jonathan apples, 

 although homogeneous, was channeled, and this variety had only very 

 small deposits of supplementary cutin. 



In general, apples showing deep-staining capacity and low incidence 

 of birefringent crystalline bodies in hypodermal cell walls had good 

 storage quality. The depth of the hypodermis or the thickness of the 

 hypodermal cell walls apparently had no bearing on the keeping 

 quality of the apples. 



Deterioration of apples in storage showed some relation to the 

 characteristics of cortex parenchyma cell walls. In Delicious and 

 Rome Beauty tissues the cell walls showed more intense overall stain- 

 ing capacity and fewer instances of rupture and birefringent bodies 

 than in the other varieties, which may be an indication of greater 

 stability in composition. 



Palatability scores for skin texture of apples from the second year's 

 crop indicated that Golden Delicious had the most tender skin and 

 Stayman the least tender. The tenderness of Golden Delicious skin 

 can be attributed to the high incidence of surface and internal inter- 

 ruptions in the cuticle, combined with shallow hypodermis. The low 

 scores for skin texture received by Stayman apples probably were 

 influenced by the very firm flesh texture; the thick cuticle and hypo- 

 dermis in the Stayman variety also could contribute to its skin 

 toughness. 



The only change in waterproofing layers due to steaming which was 

 visible microscopically was a somewhat lessened staining capacity. 

 This change, combined with softening of hypodermal cell walls, may 

 account for the more tender skins in baked than in raw apples. After 

 baking, Delicious apples had the toughest skin, although neither 

 cuticle nor hypodermis was deeper than in the other varieties. Skin 

 toughness of Delicious apples may be related to the relatively un- 

 interrupted character of the cuticle, extensive supplementary cutin 

 deposits, and the apparently more stable composition of hypodermal 

 cell walls as evidenced by deep-staining capacity. 



In the Delicious variety, separation of skin from flesh during baking 

 was negligible — less than in any other variety. The hypodermis of the 

 Delicious skin fell into a class apart from that of the other varieties, in 

 that the cell walls were most deeply stained, before and after cooking, 

 least swollen and spongy after cooking, and least subject to flaky 

 breakdown. Jonathan hypodermal cell walls swelled the most, Stay- 

 man next, and Rome Beauty next; all showed considerable flaky 

 breakdown. Hypodermal cell walls of Golden Delicious apples swelled 

 little, but they snowed other evidences of weakness after steaming. 



71 



