It even looks that the plant metabolism needs a certain degree of photorespiration and that the balance between the two pathways is achieved also through the balance of minerals (Mg/Mn/Ni…). What I think is even more relevant, is the shutdown of photosynthesis if the metabolic “conveyor belt” that makes use of assimilation products is overflowing. So shade plants probably have metabolic tendencies that can not stabilize these fluctuations as easily (as they should not have to!) and the sun-optimised ones will be much more stable if they have microbiology around the roots (to absorb surplus carb/provide K+ to enable macromolecule synthesis/provide waterstability/provide roots). If nutrition is good, heat dissipation in the chloroplasts from problems in the photosynthetic apparatus works better. as usual it is so complex – so I assume that a plant in full symbiosis and nutrition on a deep soil (that will provide cool water sucked up in the xylem) can take in a fat lot more of light and heat and also compensate better for shade on the other hand. Much will depend on the capacity of cycling the water from stem to root, out to exudate and up again without opening the stomata. Here we look again at the capacity the plant can mount root pressure (which I think is dependent on magnetism/paramagnetism to a high degree). So many screws in the system to play around with – but tuning the light intensity in a given system can be a great tool!