AUXIN-INDUCED GROWTH OF TUBER TISSUE OF JERUSALEM ARTICHOKE: II. THE RELATION TO PROTEIN AND NUCLEIC ACID METABOLISM

The following results were obtained using tissue slices excisedfrom cold-stored Jerusalem artichoke tuber. 1. Increase in protein content of the tissue was small duringthe washing (i.e. "aging"), and great in the growth phase, particularlyin washed tissue. 2. RNA content of tissue increased during the growth periodsimilarly in non-growing tissue (in water) and actively growingtissue (in 2,4-D plus KIN). 3. Both RNA and DNA increased during the washing, the increasebeing greater in RNA than in DNA. This RNA increase was enhancedby gibberellic acid. 4. 2-Thiouracil, 8-azaguanine, puromycin, and mitomycin C givenat the washing inhibited the subsequent growth. The effect ofthese inhibitors was not significant when they were given inthe growth period. 5. Mitomycin C reduced the basophilia of nuclei and made themswell, as did deoxyribonuclease. 6. The effect of inhibitors of nucleic acid metabolism was reversedto some extent by gibberellic acid and by kinetin. 7. Chloramphenicol inhibited the growth strongly if given inthe growing period, but not so strongly if given during thewashing. 8. An autoradiographic study using ³H-cytidine suggested thatRNA is synthesized in nucleus during the period of washing andis transferred to cytoplasm via nucleolus. It is conjectured that the RNA synthesized during the agingis responsible for the expansion growth to be caused later byauxin or auxin plus kinetin. (Received September 4, 1965; )