Source:
http://www.co2science.org/articles/V24/feb/a4.php
Xu, X., Wu, P, Song, H., Zhang, J.,
Zheng, S., Xing, G., Hou, L. and Li, M.
2020
Identification of candidate genes
associated with photosynthesis
in eggplant under elevated CO2.
Biotechnology & Biotechnological
Equipment 34: 1166-1175.
"CO2 is a necessary substrate for plant photosynthesis and that enriching the air with higher levels of CO2 typically enhances this key plant growth parameter.
This well-known fact has been proven in literally thousands of laboratory and field experiments conducted over the past five decades ...
... Xu et al. (2020) ... studied the photosynthetic response of eggplant (Solanum melongena) at ambient (400 ppm) and elevated (800 ppm) levels of CO2.
... Typically, nearly all CO2-enrichment studies apply CO2 enrichment for the full 24 hours of a day.
... Xu et al. ... only applied elevated CO2 for two hours per day (between 0800 and 1000), and only on sunny days.
... The results of such measurements revealed that a mere 2 hours per day of CO2 enrichment led to (1) a net photosynthetic enhancement in eggplant of 86.11%
"the application of exogenous CO2 in the greenhouse stimulated [eggplant] growth. ... via a doubling of CO2 for only a mere two hours per day on sunny days. "