Rubisco activation state assay
N. benthamiana leaves were incubated at 400 ppm CO2 until they reached steady state photosynthesis, then the CO2 was switched to 1500 ppm for a specified time. The plants were then sampled by freeze-clamp (Schrader, Wise, Wacholtz, Ort & Sharkey 2004). Rubisco activation state was assayed according to Li et al. (2019).