The paper presents the results of chemical analyses of different organs of ‘Jonica’ apple trees. The trees were dwarfed with: rootstocks (M.9 and P60), and additionally, with bark grafting (in normal and inverted position), microinterstocks (M.9, P22, M.27) and retardant (Paclobutrazol). Microinterstock is an additional way of dwarfing, where a ring of bark taken from dwarfing rootstock is grafted on the tree’s trunk. In the years 1996–1999 fruit, leaf, wood, bark and root samples of each treatment were collected. After washing, samples were dried, grounded and subjected to mineralization and analised for calcium by atomic absorption spectrophotometry. The highest concentration of Ca was noted in the bark of investigated trees (1.53% d.w.). Relatively high concentration of Ca was noted in leaves and roots (0.98% d.w. and 0.48% d.w. respectively). The lowest content was noted in wood and friuts (0.09% d.w. and 0.02% d.w.). Analised rootstocks did not affect significantly the leaves calcium content. On the contrary rootstocks influenced fruit Ca ammounts; the lower Ca content was noted in fruits from trees grafted on P60 rootstock. Bark graftage or microinterstocks did not influenced or lowered Ca fruit content. The only exception was microinterstock P22 which significantly increased fruit Ca ammounts. No correlation between leaf and fruit Ca content was found. Bark grafting and microinterstocks decreased root Ca content. This effect was especially evident in the first year after grafting.

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