栄養生長期における光と温度の相互作用 -特に分けつの発現伸長に対して-

抄録

Effects of light and tempeature on rice plants in the vegetative stage was examined with special reference to the emergence and elongation of their tillers. The varieties used were Zuiho, sensitive to light, and Norin No.20,sensitive to temperature, and to them were added two more varieties, different in plant type, Norin No.1 (many panicle type) and Zosan No.1 (heavy panicle type). In the experiment, which was carried out in the growth cabinet, light and daek temperatures were combined, their averages were maintained at 18.5℃ (L), 24.5℃ (M) and 30.5℃ (H), and the difference at 7℃ in each combination. The light period was controlled so that it could be 12 hours. The results were : 1. As the temperature grew higher, the leaves of the main stem developd more speedily according to which primary tillers also emerged. 2. In the three varieties except Zosan No.1,the first tillers in primary tillering emerged in the M and L combinations, while in the H combination they did not in any of the varieties. 3. No secondary tillering could be observed in Zosan No.1 in the H combination, suggesting a strong control by high temperature. 4. In principle, primary tillering should occur in accordance in time with the emergence of the leaves of the main stem. However, the accordance was brorken under some temperature conditions; Zosan No.1 showed even a contrary tendency. 5. Tillering does not synchronize with the emergence of the leaves of the main stem under unfavorable conditions. As the conditions grow favorable, however, tiller buds differentiated at every node grow up to be tillers to elongate, and the typical accordance system works under the most favorable circumstances, though adaptability for their environment vary to some extent with the properties of varieties.