GMO Houseplants; Will They Purify the Air in Your Home?

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Robert Pavlis

Scientists used genetic manipulation to add a rabbit gene into a houseplant to increase its ability to remove toxic VOC chemicals from the air in your home. Can these plants improve the air quality in your home?

Will the general public accept GMO houseplants? When can you expect to see this plant-animal-HEPA filter in your local nursery? It has been approved for sale in Canada.

GMO houseplants noat

Toxic Air in Your Home

The air in your home contains lots of VOC chemicals (volatile organic chemicals), like benzene, formaldehyde, and chloroform. Products such as furniture, flooring, paint, cleaning supplies and even cooking add these chemicals to the air, and several of them have been shown to be carcinogens. I’ve discussed this in detail here, Air Purifying Plants – Do They Work?

Many sites on the net claim that houseplants remove chemicals from the air in your home. The claims are highly exaggerated and unless your house is full of hundreds of large plants they have no effect on the quality of the air in your home.

Microbe Science for Gardeners Book, by Robert Pavlis

In this post I will look at a new genetically modified plant that may change all of this.

The Rabbit-Houseplant Hybrid

All mammalians, including humans, have a gene called CYP2E1 that encodes for an enzyme (cytochrome P450 2E1) which breaks down a wide range of volatile organic compounds. This enzyme is active in our liver and helps protect the body from such chemicals. It is also responsible for metabolizing alcohol.

The enzyme converts chloroform into chloride ions and carbon dioxide, which is then used in photosynthesis. Benzene is converted into phenol, which the plant uses to build cell walls.

Dr. Stuart E. Strand and his research team took this gene from a rabbit and along with some other controller genes added it into the common houseplant, pothos ivy (Epipremnum aureum). This mutated Ivy is able to produce the enzyme which works just like it does in the liver.

This is not the first time such a mutation has been made but it seems to be the first time the gene has been added to a houseplant.

The common name for Pothos Ivy is Devil’s Ivy

– will this new plant become known as the the Devil’s GMO?

What Did the Media Report

Lots of media picked up on the story and here are some of the headlines.

 

Rabbit gene turns houseplant into air detoxifier

 

Rabbit gene helps houseplant detoxify indoor air

 

Plant genetically modified with rabbit DNA able to clean pollution from air in homes

 

Genetically Modified Houseplants Could Help Save Us From Smart Home Hell

They all sound very positive and make it sound as if buying this plant will purify the air in your home. As usual, none of the headlines are correct.

Headlines are important because they represent the message that most people remember, and when incorrect they create new garden myths.

It is these headlines that contribute to the mistrust people have of scientists. Eventually people will find out that these plants don’t actually work as promoted and then they blame science for misleading them.

The authors of the research are not at fault here. They clearly say that growing these plants won’t have much effect on the air quality of your home. They also comment that, “More work is needed to confirm these findings and to establish the practical usefulness of transgenic biofilters.”

Testing the Genetically Modified Houseplant

GMO houseplants benzene, Pothos ivy removal of Benzene, ref 1
Pothos ivy removal of Benzene, ref 1, NPC is the no-plant control, WT is the wild-type plant, and VD3 is the modified plant

The GMO houseplant was tested to see how effective it was in removing chemicals. Small pieces of the plant were put into vials, the chemical being tested was added, the vial was sealed and the air inside was measured on a regular basis to monitor changes.

Tests were replicated and included both natural pothos ivy and no plant as controls.

The graph to the right shows the results for benzene.

The modified plant reduced the benzene level over an 8 day period. Note that the wild plant and no-plant control have about the same change. The unmodified plant had no real effect on benzene levels, contrary to what is reported in social media.

Another test for chloroform showed similar results, except that chloroform was removed to almost zero after 6 days.

Analyzing the Results

Extensive testing of the plants has confirmed that the genes were transferred into the plant.

The chemical removal tests described above seem to have been done properly, with replicates to show that the gene is active and removing benzene and chloroform better than wild-type pothos. The research seems well done.

The testing has the same limitations as the original work done by NASA. Plants were put into relatively small chambers, a fixed amount of chemical was injected and the air around the plant was monitored over time. In both cases the amount of chemical injected was very high compared to normal home air levels. Even the author of this study acknowledges this as a limitation for extrapolating the findings to home air.

The other big difference between homes and these small chambers is that in a home the VOCs are constantly being produced. It is not a one time injection. To have any effect at all the plants would need to be able to remove the chemicals faster than the house can produce them. This study makes no attempt to answer this very important question.

The authors acknowledge this limitation when they discuss the need for further testing, ” It is necessary to determine the removal rates at low concentrations of indoor air pollutants, the effectiveness of the formaldehyde dehydrogenase gene expressed in pothos, the effects of light and dark and photoperiod on removal, the effects of increased mixing and air flow rate in the biofilter, and whether increased VOC removal efficiencies can be achieved through biological manipulations such as increased transgene copy numbers.”

Plants in a Biofilter

One of the issues with using plants in a home to clean air is that the chemicals in the air have to be next to the plant in order for them to be removed. In fact they need to either be absorbed through the leaves or enter the plant through stomata.

Strand suggests that the solution to this problem is to keep the plants in a growth chamber, and have a fan move air from the room through the chamber creating an “enclosed, forced-air biofilter”. Think large terrarium with the ability to suck air through it. This would make the process much more efficient.

None of the above listed media titles mentioned this! A few of the articles did mention it in the body of the article, but most skipped this part entirely.

Will Mutated Houseplants Clean Our Air?

The work is very promising. There is no reason why we can’t add other genes that remove other chemicals and we should also be able to add extra copies of the same gene to make the plant more efficient.

The next generation of these plants might work as a biofilter. Given the current and near term technology, even Dr. Strand is not very positive about these plants ability to sit in a room and clean our air. He does feel the biofilter might work.

Will People Accept GMO Houseplants?

To be clear I don’t think these are GMO mutations since the GMO technology is not used, but the term is in line with the general public’s understanding of the term.

The reason the pothos ivy was selected for this work is that it does not flower either in the home or outside in North America. This means there is no worry about pollen contaminating natural plants.

The modification has nothing to do with Roundup or Monsanto, so two of the biggest arguments against GMOs don’t apply.

We don’t eat the plant, so the general public’s completely unfounded concern about eating a GMO is not a concern.

Assuming they would purify the air in our homes, will people accept GMO Houseplants?

I decided to post the question in several gardening Facebook Groups and casually monitor the responses. Many people are against GMO no matter what benefit they provide. Some don’t see the point of these plants since their current house plants clean the air just fine – they still believe that myth.

Surprisingly, 50% are open to the idea of GMO houseplants if they provide a benefit and can’t harm the environment. That is a lot more than I thought I would see.

One person voted against using the plant because of all the rabbits that would need to die in order to make the plants.

To see the full report on this social experiment, visit: GMO Houseplant Purifies Air – Will People Buy It?

References:

  1. Greatly Enhanced Removal of Volatile Organic Carcinogens by a Genetically Modified Houseplant, Pothos Ivy (Epipremnum aureum) Expressing the Mammalian Cytochrome P450 2e1 Gene Long Zhang, Ryan Routsong, and Stuart E. Strand

 

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Robert Pavlis

I have been gardening my whole life and have a science background. Besides writing and speaking about gardening, I own and operate a 6 acre private garden called Aspen Grove Gardens which now has over 3,000 perennials, grasses, shrubs and trees. Yes--I am a plantaholic!

4 thoughts on “GMO Houseplants; Will They Purify the Air in Your Home?”

  1. Mr Pavlis, I thought your review of our paper was skeptical but fair. We hope that we can prove that our plants and the biofilter will be able to make a significant improvement in indoor air quality and people’s health, but time and experiments will tell.

    Your skepticism of the claims made for houseplants’ abilities to degrade volatile organic carcinogens is well founded in my opinion. In a review of the literature we found that rates of removal for benzene or formaldehyde varied by over 10 million fold for the same plant between different labs! This difference may be explained by experimental artifact. Contact me if you are interested in more information.

    A lack of consensus in the literature findings on the removal of
    airborne benzene by houseplants: Effect of bacterial enrichment.
    Wararat Sriprapat, Stuart E. Strand. Atmospheric Environment 131 (2016) 9-16

    Reply
    • Thanks for your comments.

      Here is a simple experiment that would be interesting. Place one or more of your new plants in the center of a real room in a house. Let things equilibrate. Now measure pollutants at different distances from the plant. Might need to do this with chromatography instead of meters. Can you measure any difference as you near the plant?

      Need some way to control air movement near the plant?

      Can you demonstrate that at least the air near a plant is cleaner? Based on my understanding of how gases move through air and the rates plants remove pollutants, I would guess that except very close to a plant, there is no difference. Not sure what “very close” is.

      Reply
  2. I too read a report of this development on that excellent website Botany One. Cutting edge technology based on a popular myth.
    Snake oil!
    Eventually I might have to eat my words! – if I live long enough

    Reply

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