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Changes in endogenous hormones and H2O2 burst during shoot organogenesis in TDZ-treated Saussurea involucrate explants

Guo, Bin, He, Wei, Zhao, Yan, Wu, Yandi, Fu, Yanping, Guo, Juan, Wei, Yahui
Plant cell, tissue, and organ culture 2017 v.128 no.1 pp. 1-8
Saussurea involucrata, biochemical mechanisms, catalase, explants, exposure duration, gibberellic acid, hormones, hydrogen peroxide, leaves, organogenesis, plant tissues, superoxide dismutase, thidiazuron, urea, zeatin
Thidiazuron [N-phenyl-N-(1, 2, 3-thidiazol-5-yl) urea, TDZ] treatment significantly improved shoot morphogenesis of Saussurea involucrata Kar. Et Kir (S. involucrata) leaf explants. The biochemical mechanisms underlying TDZ-induced shoot organogenesis were investigated by measuring endogenous plant growth hormones, H₂O₂, as well as the activities of superoxide dismutase (SOD) and catalase (CAT). The levels of endogenous gibberellic A3 (GA₃) and zeatin (ZT) significantly increased in leaf explants subject to a 28-day treatment than the controls. However, extending exposure time to TDZ inhibited GA₃ accumulation. At the same time, the SOD activity increased significantly until the 28th of TDZ treatment time and the CAT activity reduced simultaneously, which was closely linked with the significant increase in H₂O₂ concentrations in the explants. And there was a sharply promotion after the 35 day of culture time if the plant tissue was always in medium contained, which was in company with the cell activity decreased. We propose that a combination of increased GA₃, ZT, and H₂O₂ concentration is the basis for the enhanced shoot morphogenesis in response to TDZ treatment. These results provide a starting point for an improved understanding of the biochemical mechanisms underlying TDZ-induced shoot organogenesis of S. involucrata.