A cytokinin plant growth regulator with diverse biological activities; increases p34cdc2-like histone H1 kinase activity, the number of cells in mitosis, and total cell number in arrested N. plumbaginifolia cells at 0.23 μM; increases GSH levels and activity of glutathione peroxidase and glutathione reductase, but reduces TBARS levels, in human skin fibroblasts at 10 μM; reduces age-related enlargement, multinucleation, and accumulation of cellular debris in human mammary skin fibroblasts at 40 μM