Current issue: 53(2)
Under compilation: 53(3)
Plants assimilate carbon dioxide from the air. Respiration of plants also produce carbon dioxide. Because the carbon dioxide level of the air is only 0.3%, only little carbon dioxide can diffuse in plants. Thus, the carbon dioxide assimilated by the plants is formed mostly in the earth when organic substances are degraded. The article describes a method to measure carbon dioxide level in the air.