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Could an artificial plant species be designed and created that lives in a vacuum - for example on the surface of our moon?
The main problems I can see immediately would be the lack of an atmosphere for respiration, the lack of microbes in the soil, and the massive temperature swings. Would it be possible to biologically engineer something able to survive and reproduce in those circumstances though?
1.: You need water - Fun fact. First "plants" on Earth started in atmosphere without any oxygen. But without water (Moon soil) you would be no go with even the most clever design ever.
2.: You need minerals - You can go away with microbes, but the plant needs to feed on something. That is how we grow most vegetables for mass production: Hydroponic planting in water enriched by all minerals what plant needs. So again, water only is not enough. Water with minerals could be a GO, but:
3.: You need stable environment. Although you could avoid a loads by clever DNA design of such plant, still, on Earth you have temperature range from -80 Celsius to +50 degree Celsius. I believe that on surface of Moon you can go more extreme ranges.
Long story short: It is engineering problem:
You need plant of a design which would keep its own micro-atmosphere (sphere like design, where plant would breathe inside such sphere)
You need a plant able to survive extreme temperatures both ways. Basically taiga wood mixed with desert cactus.
And, bonus, such plant should survive with as little water as possible (more cactus design than Siberian taiga wood)
In sci-fi setup of really developed DNA engineering, I think you could pass such idea on. But in reality I think you would crash on extreme setup of the environment.
Plants which perform photosynthesis require carbon-dioxide to grow. The metabolism of plants converts CO2 into carbon and oxygen through photosynthesis. The carbon is the main element a plant is made of. Without a carbon-dioxide atmosphere, a plant can not grow.
However, you might be able to grow mushrooms in vacuum. Fungi don't perform photosynthesis. Instead they absorb organic compounds which are or were part of other plants or animals. That means they technically do not need an atmosphere. But you will have to provide a source of nutrients. Fortunately fungi are surprisingly versatile. According to Wikipedia:
Fungi have evolved a high degree of metabolic versatility that allows them to use a diverse range of organic substrates for growth, including simple compounds such as nitrate, ammonia, acetate, or ethanol.
Many of these simple compounds have been detected in nebula, so finding a natural source of them in space isn't far-fetched.
I am not a biologist, but I doubt that you will find a fungi species on earth which grows well in vacuum because their cells evolved to be stable within 100 kPa atmospheric pressure. But you might be able to create one through genetic engineering or, when you have the time, artificial selection (create cultures, lower pressure until most of them die, wait until they regrow, lower pressure further).
A plant like bamboo? Very unlikely, however, if we go small you might make it happen. Lichen and moss might be able to be designed for such a thing. I know lichen isn't a 'plant' but algae will make chlorophyll.
Things that hug the ground would have a better chance of surviving, just look at would lichen can be found here on earth, they can live in some very inhospitable places. They might be able to hold a small atmosphere and break down the rocks and other minerals and it could handle going into stasis every time the moon turns away from the sun.
So I would expect we would start by playing with Lichen then maybe move on to mosses and go from there
I would picture this "plant" as appearing as the trunk of a Baobab. Any branches would be very short and may not even exist. Its appearance may be more similar in shape to a saguaro cactus rather than a tree. Any leaves (needles?) would be more photo-voltaic solar cells rather than being chlorophyll-based. The interior of the (water-tight, air-tight, vacuum-proof) trunk would be stocked with water, minerals, and gases that the tree would consume to live and grow.
I would assume that the purpose of such a plant would be to use specialty roots to slowly process dirt and rocks into usable materials. Resupply runs would be needed to replenish its stockpiles and to harvest anything useful it produced.
