THE USE OF AN ELECTRON MICROPROBE TO MONITOR THE UPTAKE OF CALCIUM AND CHLORIDE IN APPLES
An electron microprobe was used to follow the uptake and penetration of calcium and chloride ions in apples that had been immersed in calcium chloride solution under vacuum in order to improve storage qualities. After 2 days at 20 °C, Ca and Cl penetrated approximately half way into the apple. After 4 wk at 20 °C, both ions penetrated all the way to the coreline although relatively more Ca than Cl penetrated the inner half of the fruit. Penetration of Ca was slower in fruit held at 2 °C than at 20 °C, while that of Cl was at least as rapid at 2 °C as at 20 °C. This in situ analysis technique was also used to determine the elemental composition of specific localized structures including vascular bundles and lenticels.Key words: Calcium, chloride, apple, electron microprobe