Selective and Preferential Translocation of C14-Labeled Sugars in White Ash and Lilac

Abstract

C14 was introduced into attached leaves of ash and lilac plants either as C14O2 during photosynthesis, or as verbascose-Cl4, stachyose-Cl4, raffinose-Cl4, sucrose-Cl4, mannitol-C14, or fructose-Cl4. Biddulph''s flap technique was used to introduce the labeled sugars and yielded results comparable with those obtained after offering Cl4O2. The nonreducing sugars verbascose, stachyose, raffinose, sucrose, and mannitol were translocated while the reducing sugars melibiose, galactose, fructose, and pentose were not. The evidence suggests that there are 2 processes which control the translo-cation of sugars. One is a selective process in which only nonreducing sugars are translocated. The other results in different amounts of sugar being translocated and is called preferential translocation.