You and I both know that would take a considerable amount of side by side comparisons to determine.
.. determine what? I admit I have lost track a bit. Imo the argument about phototropism has been put to bed ... plants will respond phototropically to artificial light possessing a reasonably adequate spectrum.
Yet I am convinced there are elements present in a star that cannot be reproduced...the light spectrum emitted and processed by plants cannot be replicated over time by artificial means.
I would be interested to hear you tell me what you think those are. If we're using "elements" in a chemist's sense, ... a star is no more than a self-maintaining bright plasma, a blend of elements producing blackbody radiation at about 5700ºK.
Plasma output graph:
The white line is plasma output.
The brown line is output from a typical HPS lamp.
The rainbow-filled curve represents a plant's sensitivity to (or capacity to use) light energy.
The only other way for me to interpret "elements" would be to reach into older mystical traditions, but then we'd be talking about (when you strip away all the cultural bits) magic. cn