I'm trying to find a way to explain an alien species' ability to control plants, specifically plant growth for crops, without it being 'magic.' So they can ensure the health and size of the plants even if there is a draught, or a pestilence ect. without the help of modern technology like pesticides or sprinklers.

What I mean by 'non tool based' is that they must only need themselves to control the plants. So explanations through things like biology or chemistry, but not technology (and by that I mean the species has a computer chip in its brain or something).

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    $\begingroup$ Do you mean all plants, or a specific species (or group of species) of plants? $\endgroup$ – PlutoThePlanet Apr 24 '18 at 18:00
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    $\begingroup$ Regular agricultural techniques are not enough? Humans managed to use them to make some pretty impressive results. $\endgroup$ – Sasha Apr 24 '18 at 18:01
  • $\begingroup$ It's quite hard to understand what can and can't be used. Biology/chemistry can be used, but it has to be part of the specie itself, not developed? $\endgroup$ – Rick M. Apr 24 '18 at 18:10
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    $\begingroup$ Yes, I'm trying to find a way to explain how the alien species controls plants through some biological/chemical component of the species, not through the use of developed tools. $\endgroup$ – Teanna Schmaeh Apr 24 '18 at 18:15


And by this I don't mean anything bizarre like Marvel Comics's Venom.

This already happens in our world, in some way. Cattle such as sheep and cows eat grass. At a glance, most people would think that this is beneficial to the animal, while being solely detrimental to the plant. But the grass blades that have been munched on get a benefit as well.

Cattle saliva contain some substances that stimulate plant growth. In the absence of cattle, some kinds of grass might not grow as much, nor as healthy as they would otherwise.

Don't forget that that's not the only way in which cattle and grass interact. The waste of cows and sheep is broken down by fungi and bacteria, and the byproducts of that are important for grass.

Your species might do the same thing - by secreting different substances through different body parts, in response to different stimuli both from the plants themselves and the environment. Sentience in the animal species helps it plan and organize the application of its secretions on plants, thus acting more efficiently than if they did it by instinct alone. It also allows for actual farming.

Note that these secretions are hormones, so your fictional people are communing with plants in some way. Also notice that this does not preclude the use of technology. In fact, it synergizes very well with it. Being able to tell a plant to grow faster, form flowers, or to withold fruit formation at precise times of the year is great. Using that together with ploughs, dams and irrigation is even better.

A sample secretion as food for thought: ethylene. For humans, it is raw material for most of the plastic we produce:

Ethylene is widely used in the chemical industry, and its worldwide production (over 150 million tonnes in 2016) exceeds that of any other organic compound. Much of this production goes toward polyethylene, a widely used plastic containing polymer chains of ethylene units in various chain lengths.

But for plants, it is a hormone:

Ethylene is also an important natural plant hormone, and is used in agriculture to force the ripening of fruits.

  • $\begingroup$ The cow saliva point is really interesting! Could you by any chance list any other species that do similar things? The 'secretions' part made me think of slugs maybe? $\endgroup$ – Teanna Schmaeh Apr 24 '18 at 18:19
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    $\begingroup$ @TeannaSchmaeh Check this out: "Volicitin present in the regurgitant of beet armyworm caterpillars activates the emission of volatile organic compounds (VOCs) when in contact with damaged corn leaves. VOC emissions in turn serve as a signaling defense for the plant by attracting female parasitic wasps that prey on herbivore larvae." ncbi.nlm.nih.gov/pmc/articles/PMC341921 The symbiosis in this case is between corn and wasps... The corn tells the wasp where its prey is, and the wasp protects the corn. $\endgroup$ – The Square-Cube Law Apr 24 '18 at 18:26
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    $\begingroup$ You could make their excrements like a super food to the plants. Similar to fertilizer, just speed up the chemical process of it getting to the plant for use. You could go as far as making this a symbiotic relationship as well. $\endgroup$ – Dtb49 Apr 24 '18 at 19:55

They won't be able to anything spectacular over the short term but they can do subtle or have spectacular long term results.

Plants use a lot of chemical feedback loops in their growth. If a species was able to introduce the right chemicals at the right times in the right spots, they could affect the way the plant grows. Thus, they might make it a bit more drought resistant or make the fruit bigger at the expense of some other part of the plant.

Also, if the species is long lived and/or very patient, they can have pretty spectacular results over the long run. There is an acacia tree (I think that's the right breed) that has holes in it's branches and has fruit specifically for a breed of extremely vicious ant. If anyone disturbed that tree, the ants swarm them. This change happened over a very long time but it is pretty spectacular in how specific it is.


Many options are available pheromones, magnetic influence, light response, sound... basically anything a plant already responds to can be extruded to a control mechanism given a long enough evolutionary path with a symbiotic species...

Our old friend https://en.wikipedia.org/wiki/Ophiocordyceps could prove a fun option as well... some type of fungus could infect both the plants and the aliens... and allow some manner of shared goal... or more reasonably... enhance the aforementioned interactions...


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