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Which plant will be able to survive the condition on Mars? Does it even matter, isn't it just possible to genetically modify a plant so it can easily survive on Mars? What kind of genetically modified plant will terraform mars the quickest and won't need our help to do that?

My idea about such a plant supports the following requirements:

  • Water
  • Soil
  • Light

What my idea unfortunately won't support:

  • Oxygen
  • Temperature

The idea started with pretty basic thinking, about the plant itself but it evolved to so much more than that. Now I can't barely imagine what couldn't make it work. Anyway let's start with the plant.

The plant

There is water on Mars but it's not in a liquid state so basically plants can't use it. That's why we have to bring it with us, but we will only supply one plant. Because we are actually only growing one plant. Yes I'm talking about foothills, at least if you can call a batch of connected plants, one plant :D

Okay so let's start with growing just one plant what will spread new plants via their branches, the new plant what grows is fed through the branch. This connection should less for ever because the children plants need water from the mother plant. The martian soil should be fine, regarding this research. Then there is solar radiation. Plants just can't survive that, right?

The module

How will the module — what we've to put on the surface of Mars — look like? Well first of all the mother plant we're growing on the martian soil should be the only plant what we feed water, shelter from solar radiation. And that's why we also have to take care of the light for some plants. The water we use to feed the plant is very rare and should be recycled as much as possible. The children plants should be able to spread outside of the module but have to stay connected to the mother plant. The more children the mother plant will have, the more water is needed. That's where a rover comes in handy, one that searches for water and maintains plants what might grow outside the growing module.

The growing module is a module what contains lights, solar panels, water tank and is build in such a way so it can plant and research the mother plant. Research? Yes if we could do experiments on Mars than the whole process will go much faster!

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  • $\begingroup$ Keep water above freezing. Nature can handle the rest. $\endgroup$ – Mazura Jun 26 '16 at 3:33
  • $\begingroup$ Plants don't need oxygen, they need carbon dioxide. $\endgroup$ – Schwern Jun 26 '16 at 4:12
  • $\begingroup$ Are you meaning that "foothills" is a species of plant? You could link to it and summarize as part of the question. Even in the title, I thought it must mean "plants that grow in the foothills" or something like that. $\endgroup$ – JDługosz Jun 26 '16 at 10:02
  • $\begingroup$ Wikipedia nor Google indicates a plant called "foothills". $\endgroup$ – JDługosz Jun 26 '16 at 10:07
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    $\begingroup$ looks like something like that Pando tree. Will not work and too long. water vapor pressure, boiling point will be something like 7°C, too low for most plants. Moss, maybe, specially because it grow that way, preventing water evaporation. $\endgroup$ – MolbOrg Jun 26 '16 at 21:45
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I'm going to focus on just one part of the problems having a plant in the open on Mars will have to overcome: the atmosphere... or rather the lack of it.

Carbon dioxide

This is where plants get the carbon to build themselves. Mars's atmosphere is very thin, 0.6% the pressure as on Earth. Fortunately it's almost all carbon dioxide as opposed to the <0.4% here on Earth. Whether or not photosynthesis will work at that low a pressure is another matter...

Very low pressure

As mentioned above, the atmosphere of Mars is very, very thin. It's roughly the same as being 33 km up. For comparison, Mt Everest is not quite 9 km high. No plant on Earth evolved to deal with that low pressure. You mention genetic modification, but there's no plant to borrow genes from. It's not even clear if photosynthesis can work at that low pressure.

Liquid water on the surface of Mars is (almost) impossible.

Below 611 Pa of pressure, water will never be a liquid. It will go straight from solid to gas (sublimation).

enter image description here

The Martian atmosphere is about 600 to 1000 Pa leaving an extremely narrow range of temperatures for liquid water. On the surface of Mars, in the best conditions, liquid water can exist between 0C and 7C. This means your plant will have to survive freezing at night, and then its water wanting to boil off during the day.

Half the sunlight

Mars gets about half the sunlight Earth does. This is surmountable, lots of plants survive in the Arctic, but measures to increase sunlight absorption (ie. increase your surface area) usually conflict with measures to decrease water loss (ie. decrease your surface area).

How do you make this work?

There are extremophiles, in particular psychrophiles which use an anti-freeze to prevent water from freezing. So the freezing problem can, theoretically, be solved.

However, there is no life on Earth that can prevent their own water from boiling. Even hyperthermophiles fail when water boils.

Even if that can be overcome, perhaps by the plant maintaining an internal seal, it leaves a very narrow window during the day when water will be liquid and it's safe for the plant to "breathe".

One possibility is to use an altered photosynthetic metabolism used by desert plants called Crassulacean Acid Metabolism or CAM. They keep their stoma closed during the day to avoid water loss. At night they open their stoma to take in CO2 and exhale O2. The CO2 is stored as an acid. During the day their stoma are closed to prevent water loss, and photosynthesis happens using the stored CO2.

In order to avoid water loss from evaporation it would have to drastically reduce its surface area. Like a cactus it would probably have no leaves, just a stubby, cylindrical body to store water with photosynthesis happening on the stem. A thick skin would maintain pressure inside to prevent its internal water from boiling during the daytime.

Unfortunately reduced surface area means reduced absorption of sunlight. The CAM cycle is also inefficient. This means a much reduced amount of energy available. Like a lichen adapted to Arctic conditions, it would grow very, very slowly.

So our proposed plant...

  • Maintains an internal pressure high enough to keep its water from boiling.
  • Uses a biological anti-freeze to keep from freezing at night.
  • Uses CAM photosynthesis to only "breathe" when it's safe.
  • Has the bare minimum of surface area to reduce water loss.
  • Grows very, very slowly like a lichen due to the reduced energy intake.

The open question remains of how the plant maintains an internal pressure higher than the atmosphere to prevent its water from boiling, but still manages to pull in air.

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  • $\begingroup$ The "barrel" might maintain pressure while light enters through a transparent "window" to the photosynthesizing organs inside. Internal reflectors would also be useful to increase the amount of energy reaching the organ. $\endgroup$ – Thucydides Jun 28 '16 at 4:44

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