If someone where to use crispr to make a new plant species driving from a tough desert plant that doesn't need as much water as most plants and splices the genes with underwater algae found in the 'Abbisle zone' in the ocean could they also increase the metabolic rate to match the input and output in oxygen and co2 in a human could it work as a rebreather if used properly and contained the correct way this is an idea that I've run by a friend and we've been taking this more seriously than most ideas before it we think that if all goes well we could patent this. i do realize how much the metabolic rate would have to increase to match the breathing of the average human and the nutrients needed to support this plant with the metabolic rate so increased. if anyone could help with this then that would be most appreciated thank you very much- Sci-Man

First impressions are that you need sunlight for the photosynthetic reaction, and there's a limit to the amount of energy in each square metre. So no matter how efficient your plant becomes, it can't acquire any more solar energy without getting much much bigger. 

And of course, you would die if it turned cloudy. Or in the shade, or if you dived too deep. 

9 minutes ago, mistermack said:

First impressions are that you need sunlight for the photosynthetic reaction, and there's a limit to the amount of energy in each square metre. So no matter how efficient your plant becomes, it can't acquire any more solar energy without getting much much bigger. 

And of course, you would die if it turned cloudy. Or in the shade, or if you dived too deep. 

1

not to mention, the potential to create a plant that could produce a worldwide monoculture.