C2-substituted aromatic cytokinin sugar conjugates delay the onset of senescence by maintaining the activity of the photosynthetic apparatus

Synthetic halogenated aromatic cytokinin riboside derivatives have been tested in three cytokinin bioassays, including the wheat leaf senescence bioassay. Derivatives that strongly delayed the onset of senescence were selected and their effects on gene expression in senescent Arabidopsis leaves were investigated in microarray experiments. In addition, their effects on selected photosynthetic parameters in such leaves were determined.20