2025-11-11 ミュンヘン大学(LMU)
LMUミュンヘンの研究で、食虫植物ムシトリスミレ属(Pinguicula)がサボテンなどと同じCAM型光合成(夜にCO₂を取り込み昼に利用)を行うことが初めて確認された。これは乾燥環境への適応戦略であり、進化的に独立して39回出現したとされる。特にメキシコ産種で確認され、湿地性から乾燥適応種への進化過程を示唆する成果である。
<関連情報>
- https://www.lmu.de/en/newsroom/news-overview/news/as-in-cacti-cam-photosynthesis-discovered-in-carnivorous-plants.html
- https://onlinelibrary.wiley.com/doi/10.1111/plb.70128
CAM!食虫植物におけるCAM光合成の初めての証拠 Yes, we CAM! First evidence of CAM photosynthesis in a carnivorous plant
N. J. Fleck, T. F. E. Messerschmid, A. Fleischmann, R. C. Ferrari, G. Kadereit
Plant Biology Published: 10 November 2025
DOI:https://doi.org/10.1111/plb.70128
Abstract
- Crassulacean acid metabolism (CAM) is a photosynthetic adaptation enabling higher CO2 concentration close to Rubisco and increased water use efficiency. It evolved in at least 38 plant families, none reported to be carnivorous. Here, we investigate CAM activity in the carnivorous genus Pinguicula, so far reported as C3, with succulent leaves and distributed mainly in Central America.
- Eight species of Pinguicula, most with seasonal heterophylly, were cultivated under controlled conditions and monitored for changes in diel acidification (ΔH+) when grown with abundant or limited water availability. Additionally, leaf anatomy and gas exchange were studied in representative species.
- In the winter trial, five species had positive and significant ΔH+ 1 week after withholding water (P. agnata, P. esseriana, P. gigantea, P. laxifolia and P. moranensis). ΔH+ levels were in the range previously reported in weak, facultative CAM plants (15–30 μmol H+ g-1 FW). The summer trial revealed positive ΔH+ for most species tested, regardless of water availability. Three of the homophyllous species had an unclear pattern of CAM induction (P. emarginata, P. martinezii) or no CAM induction (P. grandiflora). Gas exchange in P. agnata found no dark CO2 assimilation, suggesting CAM cycling.
- We present the first report of CAM in a carnivorous plant, reinforcing the need to search for CAM in other families. Future work should assess reversibility of the C3-CAM transition, explore the interplay between nutrient and carbon balance, and the contribution of weak CAM to plant fitness.
