INTERCHANGE OF 14C-KINETIN AND 14C-GIBBERELLIC ACID BETWEEN BARK AND XYLEM OF WILLOW

Considerable two-way interchange of label derived from 14C-GA3 and 14C-kinetin has been shown to occur between the xylem and extra-cambial tissue of Salix viminalis L. Radial translocation of both growth substances from the transpiration stream to the sieve-tube sap has been demonstrated by the use of an aphid technique. This is the first record of the bark-xylem interchange of these two growth hormones. A high percentage of 14C-label is present in compounds other than GA3 and kinetin 8 hours after application. Mechanisms of lateral transfer are discussed together with their possible physiological significance. © 1969 Springer-Verlag.