|| 要旨トップ | 目次 |||日本生態学会第65回全国大会 (2018年3月、札幌) 講演要旨
一般講演（口頭発表） E02-03 （Oral presentation）
One of an effective global warming countermeasure is CO2 reduction in urban areas because they emit considerable amount of anthropogenic CO2. Urban landscape trees have a role of CO2 absorption by their photosynthesis in urban area. Information of (1) current status of atmospheric CO2 environment and (2) variation of photosynthetic function in urban landscape trees are essential for effective CO2 reduction. Seasonal and annual variation of the photosynthesis in a major urban landscape tree species, Ginkgo biloba was investigated from leaf expanding season to leaf fall season from 2014 to 2017 in an urban area in Kyoto city. Concentration and stable carbon isotope composition (δ13C) of ambient CO2 was measured by WS-CRDS gas analyzer. Maximum photosynthetic rate (Amax) of Ginkgo biloba was kept high from spring to summer season and then gradually declined in autumn season. This decline was related to the reductions in photosynthetic biochemistry (Vcmax, J) and stomatal conductance (gs) of Ginkgo biloba. Concentration and δ13C of ambient CO2 showed diurnal and seasonal variations, which may be influenced by changes in tree photosynthesis. We are now trying to estimate CO2 source of ambient CO2 in Kyoto city.