What gasses do plants need?

Question

What gasses do most varieties of plants take in under average conditions?

Obviously they need CO2 and O2 for photosynthesis and aerobic cellular respiration, but do they need the other gasses present here on earth like Nitrogen which they already take in through their roots? What pressures do they need to be in?

Any info, or where I could find such info, is much appreciated. My end goal is to know the exact amount of gasses that would need to be maintained in a greenhouse with irregular external conditions (like on Mars).

Answer 1

Most plants can't use other gases.  They can't even use ammonia for nitrogen; they rely on bacteria to oxidize it to nitrate, or to fix nitrogen for them.  So CO2 and O2 is it (though it's possible that they may need a buffer gas because too much O2 might be toxic, as it is to humans).