Influence of different dwarfing methods on content of microelements in apple tree organs.

The paper presents the results of chemical analyses of different organs of apple tree cv. ‘Jonica’. The trees were dwarfed with: rootstocks (M.9 and P 60), and additionally, with bark grafting (in normal and inverted position), microinterstocks (M.9, P 22, M.27) and growth retardant (Paclobutrazol). Microinterstock is an additional way of dwarfing, when a ring of bark taken from dwarfing rootstock is grafted on the tree’s trunk. In 1996–1999 fruit, leaf, wood, bark and root samples of each treatment were collected and iron, copper and zinc content analysed by atomic absorption spectroscopy. The highest concentration of Fe was noted in roots (1271 mg•kg-1 d.w.), lower – in leaves (164 mg•kg-1 d.w.) and the lowest – in bark, wood and fruit (95, 28, and 22 mg•kg-1 d.w., respectively). The highest amount of Cu was studied in leaves and bark samples (33.9 mg•kg-1 d.w. and 27.3 mg•kg-1 d.w.), whereas the lowest copper level was found in wood and fruits (4.2 mg•kg-1 d.w. and 3.4 mg•kg-1 d.w.). Mean Zn content varied from 161 mg•kg-1 d.w. (roots) to 7.0 mg•kg-1 d.w. (wood). As far as leaf microelement content is concerned, used dwarfing method had no or little effect. However, the great differences between analysed seasons were observed. Bark analysis revealed that bark grafting and microinterstocks favoured higher microelement concentrations especially below the place of graft. Bark grafting and microinterstocks significantly increased root Fe and Zn content (even 6 times as... [to full text]