AUXIN-INDUCED GROWTH OF TUBER TISSUE OF JERUSALEM ARTICHOKE

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Abstract
The following results were obtained using tissue slices excised from cold-stored Jerusalem artichoke tuber. 1. Increase in protein content of the tissue was small during the washing (i.e. “aging”), and great in the growth phase, particularly in washed tissue. 2. RNA content of tissue increased during the growth period similarly in non-growing tissue (in water) and actively growing tissue (in 2,4-D plus KIN). 3. Both RNA and DNA increased during the washing, the increase being greater in RNA than in DNA. This RNA increase was enhanced by gibberellic acid. 4. 2-Thiouracil, 8-azaguanine, puromycin, and mitomycin C given at the washing inhibited the subsequent growth. The effect of these inhibitors was not significant when they were given in the growth period. 5. Mitomycin C reduced the basophilia of nuclei and made them swell, as did deoxyribonuclease. 6. The effect of inhibitors of nucleic acid metabolism was reversed to some extent by gibberellic acid and by kinetin. 7. Chloramphenicol inhibited the growth strongly if given in the growing period, but not so strongly if given during the washing. 8. An autoradiographic study using 3H-cytidine suggested that RNA is synthesized in nucleus during the period of washing and is transferred to cytoplasm via nucleolus. It is conjectured that the RNA synthesized during the aging is responsible for the expansion growth to be caused later by auxin or auxin plus kinetin.