대기 중 CO₂ 상승 조건에서 재배되는 콩의 광합성과 생장 반응의 분석 = Photosynthesis and Growth Responses of Soybean (Glycine max Merr.) under Elevated CO₂ Conditions

다국어 초록 (Multilingual Abstract)

The effects of elevated atmospheric CO₂ on growth and photosynthesis of soybean (Glycine max Merr.) were investigated to predict its productivity under elevated CO₂ levels in the future. Soybean grown for 6 weeks showed significant increase in vegetative growth, based on plant height, leaf characteristics (area, length, and width), and the SPAD-502 chlorophyll meter value (SPAD value) under elevated CO₂ conditions (800 μmol/mol) compared to ambient CO₂ conditions (400 μmol/mol). Under elevated CO₂ conditions, the photosynthetic rate (A) increased although photosystem II (PS II) photochemical activity (F_v/F_m) decreased. The maximum photosynthetic rate (A_max) was higher under elevated CO₂ conditions than under ambient CO₂ conditions, whereas the maximum electron transport rate (J_max) was lower under elevated CO₂ conditions compared to ambient CO₂ conditions. The optimal temperature for photosynthesis shifted significantly by approximately 3°C under the elevated CO₂ conditions. With the increase in temperature, the photosynthetic rate increased below the optimal temperature (approximately 30°C) and decreased above the optimal temperature, whereas the dark respiration rate (R_d) increased continuously regardless of the optimal temperature. The difference in photosynthetic rate between ambient and elevated CO₂ conditions was greatest near the optimal temperature. These results indicate that future increases in CO₂ will increase productivity by increasing the photosynthetic rate, although it may cause damage to the PS II reaction center as suggested by decreases in F_v/F_m, in soybean.