I just started thinking about a fictional universe where humans have colonized more or less any habitable planet (there is a huge concentration of habitable planets) and I'm trying to write down different planetary systems with different environments and stuff.
I thought about a planetary system where most of the planets have humans but, since the first expeditions found this planet and started setting up colonies, they found out something strange. On this planet there are no plants or any vegetation. The oxygen came from deep inside the planet, where atoms in water molecules are separated in some way I haven't yet thought of (but this is another problem for the future me).
Now, in the air of this planet there is also a gas that kill any plant they try to farm. I'm thinking about some toxic interaction with photosynthesis. The only plants that are farmed here grow in greenhouses and they cost a lot. Wood and paper are very expensive, as are vegetables. This problem persists until someone finds a plant, from another planet or created in a lab, that can live there. The question is:
- Is there anything like the gas I thought about that exists and that I can refer to? Remember that this thing is toxic only for plants.
- If the thing with the photosynthesis is acceptable, how can the "new plant" grow without photosynthesis?