The AOG (accelerated optimal growth) concept for rapidly producing
deciduous forest tree seedlings used continuous fluorescent light with
plants grown in greenhouses. Here's one of the AOG articles available
Wood, B.W. and Hanover, J.W. 1981. Accelerating the growth of black
walnut seedlings. Tree Planters' Notes 32(2):35-38.
The light level AOG used was low, about 2.5% to 5% of full summer
sunlight. It was meant to extend the photoperiod, not to increase
David R. Hershey