Growth Responses of Wasabi Planlets under Different Temperature Regimes During Photoautotrophic Micropropagation

抄録

    Wasabi (Wasabia japonica Matsumura) was grown under photoautotrophic micropropagation conditions using nine temperature regimes by combining day temperatures of 10^°C - 26^°C with night temperatures of 10^°C - 26^°C. Temperature-related variations in relative growth rate (RGR) were analyzed by growth analysis. After 28 days of culture, maximum dry weight was measured at a constant air temperature of 18^°C/18^°C. This study showed that the relative contributions of leaf area ratio (LAR) and net assimilation rate (NAR) to RGR depended on the growth temperature. An increase in NAR was responsible for an increase in RGR in the low-temperature range of 10^°C -18^°C, whereas a decrease in RGR in the high-temperature range of 18^°C - 26^°C was attributable to a decrease in NAR and LAR. In the low-temperature range, variation in specific leaf area (SLA) accounted for the differences in LAR. In addition, although the contribution of leaf mass ratio to the differences in LAR was enhanced in the high-temperature range, temperature-induced decreases in LAR were largely because of decreases in SLA. The plasticity of growth responses of wasabi plantlets to temperature was very different across the two temperature ranges.