|| 要旨トップ | 目次 |||日本生態学会第61回全国大会 (2014年3月、広島) 講演要旨
一般講演（口頭発表） F1-17 (Oral presentation)
There are increasing evidences showing that mesophyll conductance for CO2 diffusion (gm) limits leaf photosynthesis as well as, or even more than, stomatal conductance (gs). Although gm was widely reported for seed plants, gm of ferns was reported limitedly. We selected five temperate fern species to estimate their gm using stable carbon isotope method. Then, the mesophyll anatomies of fronds were observed using light microscope and transmission electron microscope to estimate their effects on gm. If our data were plotted together with the data of seed plant in the previous studies, gm values were positively correlated with Sc, surface area of chloroplast facing to interceller air space, while they were negatively correlated with cell wall thickness, which suggests that low Sc with large cell wall thickness of ferns was important factors that explain why gm of ferns is lower than those of seed plants. Thereafter, the response of gm and gs to changing atmospheric CO2 was observed. Ferns lacked gs response to CO2. The gm of ferns responded more rapidly to changes in CO2 than gs, which is similar to seed plants. These results suggest that mechanism for gm response to CO2 may be different from that for gs response to CO2.