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Over the past two to three years, considerable progress has been achieved in the study of the cytokinin action mechanism. Genes encoding isopentenyltransferase, a key enzyme of the cytokinin synthesis in higher plants, were discovered. The membrane receptor for cytokinin was detected. The cytokinin primary response genes were found. Protein transcription factors involved in the control of these genes were isolated. Nuclear cytokinin-binding proteins, which control, in complex with cytokinin, transcription in nuclei, were studied. Fundamentally new results were obtained about cytokinin localization in cell organelles. Cytokinin-binding proteins, which are involved in the cytokinin-dependent regulation of chloroplast-genome transcription, were isolated from higher-plant chloroplasts. New evidence concerning the interaction between cytokinins and nitrogen metabolism was obtained. We surveyed the most important recent advances in the field of the study of cytokinins, analyzed the current state of the problem, and considered the possible pathways for further cytokinin investigation.