© 1987 Heron Publishing—Victoria, Canada
Growth and the composition and transport of carbohydrate in compatible and incompatible peach/plum grafts
A. Moing (1), G. Salesses (1) and P. H. Saglio (2)
1. Station d’Arboriculture Fruitière, Institut National de la Recherche Agronomique, Centre de Recherche de Bordeaux, 33140 Pont
de la Maye, France / 2. Station de Physiologie Végétale, Institut National de la Recherche Agronomique, Centre de Recherche de Bordeaux, 33140 Pont
de la Maye, France / Received March 25, 1987
Summary
The growth of scions and rootstocks of compatible (Prunus persica L. Batsch cv. Springtime/Prunus cerasifera L. Ehrh. cv. myrobolan P2032) and incompatible (Prunus persica L. Batsch cv. Springtime/Prunus cerasifera L. Ehrh. cv. myrobolan P18) peach/plum grafts were compared. The composition of soluble carbohydrates in phloem and cortical
tissues of both peach/plum grafts and ungrafted plums and the translocation of these compounds across the union of grafted
plants were examined. Sorbitol and sucrose were the dominant sugars in the phloem and cortical tissues of plum. A cyanogenic
glycoside, prunasin, was present in peach tissues in amounts equivalent to those of sorbitol or sucrose, whereas only small
amounts of prunasin were detected in plum tissues. The concentration of prunasin was significantly higher in the phloem of
the P18 rootstock of the incompatible graft. Sorbitol was the only sugar significantly depleted in rootstock tissues of the
incompatible graft when the first foliar symptoms of graft incompatibility became evident. Translocation studies with 1-14C-deoxyglucose showed that the relative distribution of radioactivity across the graft union was similar in both compatible
and incompatible grafts. However, the total amount of radioactivity translocated across the incompatible graft was less than
one-third of that translocated across the compatible graft. The results are consistent with the hypothesis of a progressive
poisoning of the root system in the incompatible graft by a compound synthesized in peach foliage. The role of prunasin as
a possible candidate is discussed.
