Strigolactones are transported from roots to shoots, although not through the xylem

Abstract

Strigolactones (SLs) mainly produced in roots move upward to shoots and inhibit axillary bud outgrowth. However, SLs were not detected by LC-MS/MS in xylem saps collected from rice, tomato, cucumber, tobacco, sorghum, and Arabidopsis. d₁-Orobanchol and d₆-4-deoxyorobanchol that were fed to roots of rice plants were detected in shoots harvested 20 hr after treatment, although not in the xylem sap. These results imply that both endogenous and exogenous SLs are transported from roots to shoots, although not through the xylem.