AUTORADIOGRAPHIC LOCALIZATION OF ⁴⁵CA AND ³⁶Cl AFTER POSTHARVEST DIPPING OF APPLE FRUITS

The aim of the study was to obtain some information about the fate of calcium on a cellular level after postharvest dipping of apple fruits (2 per cent CaCl₂ plus 0.3 per cent keltrol (a xanthan gum) thickener) and to elucidate whether and to what extent chloride may also penetrate through the skin.

The results showed that chloride migrated into the cortex tissue, increasingly with time of storage (see Table 54.1). Autoradiographs revealed that

Table available in full text only

after dipping of Cox’s Orange Pippin or Golden Delicious apples either with ⁴⁵CaCl₂ or Ca³⁶Cl₂ solution the calyx and stem base cavity were marked sites of entry of the radioactivity.
After three months storage at 4°C, most of the chloride was retained in the cortex region whereas calcium was distributed deeper, reaching the centre of the fruit.
Unlike the chloride, calcium was obviously present in or near the vascular tissues.
Penetration and migration of calcium was related to the concentration in the applied solution.
Compared with ⁴⁵Ca, the monovalent cations ²²Na and ⁸⁶Rb (tracer for potassium) once absorbed through the skin, were much more mobile within the fruit.

Symposium on Mineral Nutrition and Fruit Quality of Temperate Zone Fruit Trees

J. WIENEKE

https://doi.org/10.17660/ActaHortic.1980.92.55