明暗期の気温がコチョウランのCO_2吸収に及ぼす影響 Effects of Temperature during Light and Dark Periods on CO_2 Absorption of Phalaenopsis Plants
Carbon dioxide absorption rate or net photosynthesis rate of Phalaenopsis, a CAM species, was precisely measured using a chamber built in this study. Environmental controls of the chamber, including irradiance, air temperature, and CO<SUB>2</SUB> concentration, were proved to be accurate. CO<SUB>2</SUB> absorption rate was calculated from changes in CO<SUB>2</SUB> concentration inside the air-tight chamber. A metal-halide high pressure discharge lamp (400 W) was used as a light source. Data acquisition and CO<SUB>2</SUB> control were done by a programmable data logger.<BR>With 32 plants, CO<SUB>2</SUB> absorption rate was measured at 20, 25, and 30°C either during the dark period (12h) or during the light period (12h). When air temperature during the dark period was 25°C, CO<SUB>2</SUB> absorption rate during the light period was highest at 20°C and decreased as temperature increased to 25 and 30°C. When the temperature during the light period was fixed to 25°C, CO<SUB>2</SUB> absorption rate was higher when the temperature was lower, although the rate was the same during the light period. Since, both in light and dark periods, we did not observe differences in CO<SUB>2</SUB>, absorption rates when temperature was the same regardless of the temperature treatments, daily total of CO<SUB>2</SUB> absorption was also higher when treatment temperature was lower.<BR>While the results showed that the CO<SUB>2</SUB> absorption was largest at 20°C, growth rate of <I>Phalaenopsis</I> has been considered to have a peak at a considerably higher temperature than 20°C. We thought that this was because of higher leaf expansion rate at higher temperature than at 20°C, resulting a higher CO<SUB>2</SUB> absorption rate per plant.
植物工場学会誌 13(2), 137-142, 2001-06-01
JAPANESE SOCIETY OF AGRICULTURAL, BIOLOGICAL AND ENVIRONMENTAL ENGINEERS AND SCIENTISTS