各種補光がホウレンソウの生育と抽苔, 花芽分化に及ぼす影響 Effects of Supplemental Lighting on Growth, Bolting and Flower Formation of Spinach
Effects of supplemental lighting on growth, bolting and flower formation of spinach (<I>Spinacia oleracea</I> L.), a long-day rosette plant, were investigated to obtain a higher efficiency of cultivation in a plant factory. Cultivation was performed under the following three conditions of irradiation using fluorescent lamps. Control : Photoperiod was 12 hr per day and light intensity of PPFD was 195 μmol·m<SUP>-2</SUP>·s<SUP>-1</SUP>. Supplemental lighting under the same conditions as daytime (SLD) : Irradiation was continuous and the light intensity was the same as that of control. Supplemental lighting under a lower light intensity than daytime (SLL) : The light intensity was the same as that of the control during a 12hr photoperiod per day, while remainder of the photoperiod was at 26 μmol·m<SUP>-2</SUP>·s<SUP>-1</SUP>. Spinach plants, which can be harvested, were obtained at 42, 21 and 28 days under control, SLD and SLL, respectively. Bolting and flower formation were only observed in SLL up to these cultivation times. Remarkable differences between the control and SLD were not observed in size, fresh weight and dry weight of spinach, and the morphology of spinach (leaf and petiol). Also, nitrogen, chlorophyll a, b and ascorbate concentrations were similar. Concentration of oxalate in SLD was similar or lower than the value generally reported, although it was higher than that in the control.<BR>The duration of cultivation in SLD was half that in the control, although the total irradiation during cultivation between the control and SLD was the same (Control : 195 μmol·m<SUP>-2</SUP>·s<SUP>-1</SUP>×12 hr/day×42 day, SLD : 195μmol·m<SUP>-2</SUP>·s<SUP>-1</SUP>×24 hr/day×21 day). Therefore, the production per year in SLD was twice the production in the control. Therefore, an efficient cultivation method was established in this report.
植物工場学会誌 13(3), 174-182, 2001-09-01
JAPANESE SOCIETY OF AGRICULTURAL, BIOLOGICAL AND ENVIRONMENTAL ENGINEERS AND SCIENTISTS