|| 要旨トップ | 目次 |||日本生態学会第59回全国大会 (2012年3月，大津) 講演要旨
一般講演（ポスター発表） P3-021A (Poster presentation)
There is a strong trade-off relationship between the catalytic turnover rate (kcat) and affinity to CO2 (Km(CO2)) of Rubisco. For example, C4 Rubisco show Km(CO2) and kcat much higher than C3 Rubisco. This can be understood as adaptation to the very high chloroplast CO2 level. Even among C3 species, we can see a clear trade-off. Plants adapted to cold environments, such as wheat, have high Km(CO2)-kcat Rubisco, while those adapted to warm / hot environments, such as rice, tend to have low Km(CO2)-kcat Rubisco. At low temperatures where the CO2 concentration in the stroma is high but the maximum rate of enzyme is suppressed by the low temperatures, the increase in kcat may be essential to maintain the high photosynthetic rate. At high temperatures, the inverse would be the case. Optimal Rubisco kinetic parameters in the high CO2 world, predicted by a simple photosynthesis model that takes stomatal conductance, mesophyll conductance, Rubisco kinetics and the temperature effects on these parameters into account, will be discussed.