温度処理に伴うテッポウユリ球根茎頂部の組織化学的変化に関する研究

Abstract

Effects of warm and cold storage temperatures on sprouting and flowering of bulbs in Lilium longiflorum THUMB., ‘Georgia’ and ‘Hinomoto’, were studied. Quantitative changes of RNA content and mitosis in the apical meristem of bulbs during, storage were observed by histochemical procedure.The results obtained were as follows:1. A large amount of RNA, demonstrated by methylgreen-pyronin method, was observed in the cytoplasm of cells at the site of leaf initiation. The measurement by microspectrophotometry showed that the RNA content of cells in the apex of daughter bulb decreased progressively from June, and almost disappeared in middle August in field conditions.2. Mitosis in the apical meristem of daughter bulbs decreased gradually from flowering time, and nearly disappeared at the beginning of July in the field.3. Sprouting of early lifted bulbs, which contained a large amount of RNA in the cells of the meristem, was promoted by warm storage (30°C for 30-35 days). The RNA content in the meristem of bulbs was decreased by the warm treatment.4. The plant grown in 20°C phytotron in summer, continued to differentiate scally leaves in their daughter bulbs until November. And hence sprouting of daughter bulbs was delayed extremely.5. The RNA content of cells in the apical meristem of bulbs increased progressively after the beginning of cold storage, cells in the mitotic state appeared in the apical meristem of the bulbs.6. In the experiment of cold storage, the earliest cell division in the apical menstem was observed in 15°C treated bulbs. In those bulbs, the number of cells in mitotic state reached its maximum two weeks after the start of cold storage. On the other hand, cell division was not observed for a long time in bulbs stored at 3°C, in spite of the increase of RNA content in the apical tissue.7. The earliest sprouting of buds was observed in the bulbs stored at 15°C, and the earliest flowering was observed in the lot of 9°C.