Analyzing the effect of light on lettuce Fv/Fm and growth by machine learning

•The OLS showed 140.8 μmol·m−2·s−1 was the optimal PPFD in constant light.•Short-time high light can increase lettuce's ability of light adaption.•The appropriate domestication PPFD is in 290–480 μmol·m−2·s−1 at fluctuating light.•The best PPFD was proved 150 μmol·m−2·s−1 in the stable constant light.•The light in the acclimation zone is not suitable for the long-term growth of lettuce.