another source for some background reading. this time the focus is the ranges of CO2 that are necessary to maintain photosynthesis in varying photosynthetic photon flux densities, temperature and CO2 conditions
https://www.ncbi.nlm.nih.gov/pmc/articl ... cle_27.pdf
Effect of different photosynthetic photon flux densities (0, 500, 1000, 1500 and 2000 μmol m-2s-1), temperatures (20, 25,
30, 35 and 40 oC) and CO2 concentrations (250, 350, 450, 550, 650 and 750 μmol mol-1) on gas and water vapour exchange
characteristics of Cannabis sativa L. were studied to determine the suitable and efficient environmental conditions for its
indoor mass cultivation for pharmaceutical uses. The rate of photosynthesis (PN) and water use efficiency (WUE) of Cannabis
sativa increased with photosynthetic photon flux densities (PPFD) at the lower temperatures (20-25 oC).