Acts in the cytokinin signal transduction pathway that regulates spore germination. Required for the maintenance of spore dormancy. Does not appear to act as a cytokinin receptor. Probably undergoes ATP-dependent autophosphorylation at a conserved histidine residue in the kinase core, which is followed by transfer of the phosphoryl group to a conserved aspartate residue in the receiver domain. ATP + protein L-histidine = ADP + protein N-phospho-L-histidine. Expressed in growing cells at low levels. Expression increases following initiation of development. Peaks around 12 hours (tipped aggregate stage), and remains at a high level throughout the remainder of development.