Induction of DNA synthesis by 2,4-dichlorophenoxyacetic acid during callus induction in Jerusalem artichoke tuber tissues |
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Authors: | YASUO YAJIMA TAKESHI YASUDA YASUYUKI YAMADA |
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Affiliation: | Department of Agricultural Chemistry, Kyoto University, Kyoto 606, Japan |
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Abstract: | During the induction of DNA synthesis in Jerusalem artichoke (Helianthus tuberosus L.) tuber by 2,4-D, the 2-14C-2, 4-D from the agar medium rapidly incorporated into the ethanol soluble and insoluble fractions. Although the 2,4-D level in the ethanol soluble fraction decreased on transplantation of the tissue from the 2-14C-2,4-D medium to medium without the auxin, its level in the buffer-soluble and -insoluble macromolecular fractions increased. The purified, buffer-insoluble macromolecules were chromatin. The 2,4-D binding to chromatin particularly increased during DNA synthesis. The histone contents of chromatin decreased as DNA synthesis progressed. The polyacrylamide gel electrophoretic patterns of the histones showed a decrease in the moderately lysine-rich histone fraction as compared to other fractions. Thus, the decrease in the histone level caused by 2,4-D and the presence of the 2,4-D moderately lysine-rich histone complex may be closely related to the induction of DNA synthesis by 2,4-D in cells. |
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