I already googled it when you placed a seed of doubt in my mind, believing me to think my old science school teacher was actually a numpty. Lol.At night, when there is no light available, the green plants don't photosynthesize. And no, they do not consume oxygen, they GIVE oxygen, they only consume CO2, light, water and nutrients nitrogen based i.e. Tort pee/poo missed in my spot cleaning is food for green plants, so it's win-win situation. I haven't figured out how to include links from my mobile devices, but there's tons of easy to "digest" info on plant life on the net. Just google PHOTOSYTHESIS and you'll find all kinds of easy diagrams as well as detailed scientific stuff on it.
I totally understand your concern about the air quality with closed chambers. That was my worry too. That's what drove my decision to aim for heavily planted chamber with all live plants and substrate containing tiny "clean-up crew"
Found this.
http://scienceline.ucsb.edu/getkey.php?key=760