The studies on redistribution of boron in apple trees as a result of leaf boron application

Redistribution of boron (B) within apple trees (Malus domestica Borkh.) as a result of leaf B application was examined. The experiments were canied out in a greenhouse on M.26 apple rootstock and in field conditions on five-year-old 'Elstar' and 'Szampion' apple trees grafted on M.26 rootstock. Boron was applied in a form of boric acid solution. It was found that leaf B application resulted in movement of B to leaves, flowers and apple fiuits untreated with B. These results clearly showed that B was retranslocated within apple tree. The retranslocation of B within apple trees took place when leaf B applications were done both in summer and autumn. Additionally, it was observed that B from leaf application had paiticularly high ability of movement within plant at insufficient B content (0,2μM) in solution. Generally, these data indicated that B within apple trees was transported in phloem, however mechanism of this phenomenon has not been well known yet. Thus, leaf B application of apple trees can be more successful treatment in reduction of B deficiency in plants compared to soil B application