Investigating the often overlooked evolutionary role of photosynthetic plasticity under fluctuating [O2]:[CO2], Yiotis et al. assess mature plants from two angiosperms, two monilophytes and Ginkgo biloba acclimated to a Triassic-Jurassic boundary (TJB) atmosphere and their photosynthetic plasticity using gas exchange and chlorophyll fluorescence methods.
Contrary to monilophytes, Ginkgo photorespires heavily and displays increased heat dissipation and severe photodamage when exposed to a TJB atmosphere. The observed photodamage reflects Ginkgo’s inability to divert photosynthetic electron flow to sinks other than photosynthesis and photorespiration, and provides insights into the underlying mechanism of Ginkgoales’ near extinction and ferns’ proliferation across the TJB.
Yiotis, C., Evans-Fitz.Gerald, C., & McElwain, J. C. (2017). Differences in the photosynthetic plasticity of ferns and Ginkgo grown in experimentally controlled low [O2]:[CO2] atmospheres may explain their contrasting ecological fate across the Triassic–Jurassic mass extinction boundary. Annals of Botany, 119(8), 1385–1395. https://doi.org/10.1093/aob/mcx018