INTERRELATIONSHIPS BETWEEN CELL-SHAPE, CE LL ARRANGEMENT, PROPORTION OF CELL-WALL AREA TO RADIAL SECTION AREA OF EPIDERMAL AND SUBEPIDERMALTISSUES AND CRACKING SUSCEPTIBILITIES IN APPLE CULTIVARS

Several variables, e. g. cell shape, cell arrangemnt in the peel tissu e, and proportion of the cell wall area to the radial section area wer e measured at harvest in 14 apple cultivars. The data were analyzed in relation to : 1) the 4 indices of susceptibility to fruit cracking, 2 ) the distributions of density of fracture on a fruit surface, 3) the occurrence of fine cracks and 4) the physical properites of the peels. It was evident from the analysis that cultivars possessing the follow ing characters were more susceptible to fruit cracking : a) flatter ce lls in the outer cell layers, b) larger tangential and radial cell dia meters in the inner and the outer layers, c) larger cell surface areas , d) larger differences in cell surface area between the two layers, a nd e) higher percentage of cell wall area stained by fast green or saf ranine in the radial section area.