Since CK bases/nucleosides are proposed to be the active form of this growth regulator, metabolism by the salvage cycle enzymes could affect the level of active hormone in a plant cell.
Although progress has been made on characterizing adenine salvage metabolism, it remains unclear as to whether plant
cells utilize these enzymes for CK interconversion in vivo.
Further genetic analysis coupled with more sensitive measurements of the CK constituents in relevant mutants will be necessary to resolve this issue.