Fig. 1
From: Q&A: How do plants respond to cytokinins and what is their importance?
Structure and composition of cytokinins. a Structures of various cytokinins (CKs). N 6-(Δ2-isopentenyl)adenine (iP), trans-zeatin (tZ), cis-zeatin (cZ), dihydrozeatin (DZ), and ortho-topolin (oT) are shown as representative natural CKs. Kinetin and thidiazuron (TDZ) may activate cytokinin receptors when administered, but are not physiological regulators of plant growth. b Pie charts showing relative abundance of cytokinin species in shoots of Arabidopsis thaliana (left) and Oryza sativa (right). The upper charts show side chain-variant breakdown: tZ and its conjugates (tZ-type), iP and its conjugates (iP-type), and cZ and its conjugates (cZ-type) cytokinins. The lower charts show conjugate-variant breakdown: active form (CK), ribosides (CK-ribosides), ribotides (CK-ribotides), and glucosides (CK-glucosides). Calculations are based on typical quantification data from [31] and [28] for Arabidopsis and rice, respectively. FW fresh weight