スギの花成反応におよぼすジベレリン濃度と温度条件

抄録

Two-year-old clonal materials of Cryptomeria japonica D. DON were kept at three alternating sets of temperatures: 30°C for day (6:00a.m. to 6:00p.m.) and 25°C at night (6:00p.m. to 6:00a.m.), 25°C for day and 20°C at night, and 20°C for day and 15°C at night. Seedlings were sprayed with gibberellin (GA₃) solutions (50, 100, 200, 300, and 400ppm) two weeks after initiating the experiment. Among concentrations of GA₃, significant differences were seen in flower development: that is, more male strobili were formed with lower concentrations of GA₃, whereas high concentrations of GA₃ reduced the number of male strobili formed. In contrast, female strobili were formed with high concentrations of GA₃. Male and female strobili were formed under the alternating temperature conditions of 20_??_15°C and 25_??_20°C more than under 30_??_25°C. The height growth of seedlings was promoted more with 100, 200, and 300ppm concentrations of GA₃ than with higher and lower concentrations.