Plant Nursery In Space?

Your point about oxygen as an industrial byproduct in space settlements may
be a good one. I'm also told (although I haven't yet seen the source
documents) that research is proceeding on man-made photosynthesizers. I
hear that microchip-sized photosynthesizers can create oxygen by a variety
of chemical processes (thereby permitting them to crank out a number of
other chemicals in the process), and that these little wonders promise
orders of magnitude more efficiency than an equivalent weight of plant
material.