ACCUMULATION OF PHENOLIC-COMPOUNDS ABOVE THE GRAFT UNION OF CHERRY TREES

Sweet cherry cultivars were grafted on Prunus cerasus. It was investigated whether phenolic compounds accumulate in the cambium-phloem or cortical parenchyma of the scion towards the union. Totally nine flavan-3-ols separated by HPLC showed a general increase in concentrations towards the union. The same was true for the two flavonoids genistin and prunin. In a separate study, phloem and cambium were analyzed independently. Prunin was more concentrated in the cambium as compared to the phloem. (+)-catechin, p-coumaroyl glucose and dihydrowogonin-7-glucoside were higher in the phloem as compared to cambium. It is concluded that a special grafting stress triggers the accumulation of some phenolic compounds above the union.