Article only looks at warming but plants are changing in response to eC02 especially via falling lignin (high lignin reduces flammability), Ziska is a good place to start:
https://onlinelibrary.wiley.com/doi/10.1111/j.1365-2486.2005.... There's surprisingly little research on eCO2 cell-level changes in plants, once CO2 went above 300ppm it ceased to be beneficial to humans.