2008 年 20 巻 3 号 p. 119-124
As a basic study on the development of closed-type cultivation system for Japanese horseradish, the effects of light intensity and light period on the growth of Japanese horseradish (Wasabia japonica Matsum. cv. Green Magic) were investigated. Cultivation was performed indoor using circulation type hydroponics system and white fluorescent lamps. (Experiment 1) Plants were grown under four conditions of photosynthetic photon flux (PPF) on the cultivation panel (60, 110, 150, 290 μmol m-2 s-1) with fixing light period at 12 h d-1. The air temperature was kept at 17°C during the light period and 14°C during the dark period. The liquid temperature and EC of nutrient solution were controlled at 13°C and 1.3 dS m-1, respectively. (Experiment 2) Plants were grown under three conditions of light period (8, 12, 16 h d-1) with fixing PPF on the cultivation panel at 100 μmol m-2 s-1. Other environmental conditions in Exp. 2 were same to those set in Exp. 1. Vegetative growth was greater with increasing PPF and light period, but PPF of 110 μmol m-2 s-1 and light period of 12 h d-1 were the most efficient in comparison of dry matter production per electric power consumption for lighting. Also, the possibility of occurrence of photoinhibition was suggested under PPF of 290 μmol m-2 s-1 in Exp. 1.