Happy New Year everyone!!
To kick off the new year here is a post about some uses of plants that you may not have known about…
Phytoremediation is a fancy way of saying ‘using plants to remove contamination’.
There are many ways in which chemical and biological contaminants can get into the environment- causing contaminated soil and ground water. Contaminations like this can be really hard to remove- requiring pretty damaging processes like soil incineration, and chemical washing, and in extreme circumstances the complete removal of contaminated areas. These processes, as well as causing damage themselves to the environment (in the short term), are time consuming and expensive.
But, there is another way- plants.
Diagram of the process of phytoremediation. (source: Wikimedia commons)
There are some plants which are able to remove contaminating chemicals from the soil on which they are growing- cleaning the soil! This property of plants is now being exploited to help with the clean up of contamination- and is particularly useful in areas where it would be unwise to send people or disturb the earth, such as old army ranges where unexploded ammo could be lurking, or old bioreactor sites.
In summer 2017 I went to a talk by Professor Neil Bruce (University of York) which told of probably the most exciting plant research project around- the use of plants to remove the explosives RDX and TNT from military ranges. RDX and TNT are toxic, explosive and mutagenic- and have a huge impact on both the environment and human health. Unfortunately, these compounds can also get into run off water, and spread contamination into other environmental areas. As RDX and TNT are used as explosives on military ranges- many of which are still active, an alternative method of removing these contaminants- which doesn’t require any disturbance of the area- would be preferred!
Some plants have the innate ability to detoxify low levels of TNT. However, high levels of TNT are not good for plants, as TNT is a potent phytotoxin. But, by researching plants which have the ability to detoxify TNT, and identifying the pathways involved a new breed of super TNT-detoxifying plants could be coming soon. A plant capable of detoxifying these toxic chemicals (simply by growing) in potentially dangerous zones, would be extremely beneficial- and would offer a inexpensive, safer, and less time consuming alternative to current methods of chemical detoxification.
Heavy Metal Removal
A slightly less ‘exciting’, but still highly important clean up by plants is the removal of heavy metals from soil such as Lead or Cadmium. Contamination by heavy metals can occur naturally via weathering of rocks, or volcanic eruptions, but is also man made. These heavy metals are not good for humans, or animals in general, and due to their long-term persistence in the environment (for Lead up to 150 years) could potentially cause damage to us for many many years.
Geraniums: work by Prof Praveen Saxena (university of Guelph) has shown gernaiums can absorb high levels of heavy metals from soils. (source: wikimedia)
Again, although many plants are able to cope with low levels of heavy metals, and can successfully detoxify contaminated soil, high levels of heavy metals are not good for plants- work is currently being undertaken in many labs to improve the efficiency of heavy metal detoxification in plants. In the meantime phytoremediation crops are commonly being grown next to ‘contamination zones’ such as factories to help reduce the effect of contamination on the environment- hopefully with the ongoing research the efficiency of these phytoremediation crops will increase further!
Plants as air fresheners
House plants not only brighten up the room, but can also purify the air for you- how cool is that!
In the late 1980’s NASA and the Associated Landscape Contractors of America studied houseplants and their ability to purify are in space facilities. It was found that several plants are able to filter out common volatile compounds such as benzene, formaldehyde and trichloroethylene from the air.
Peace Lily: which is able to filter Trichloroethylene, xylene, formaldehyde, benzene and ammonia from the air (source: Wikimedia commons)
Efficient air cleaning can be achieved by 1 plant per 100 square feet of indoor space- with one of the plants recognised as ‘air-cleaning’ plants- check out the list here.
Fuel from Algae
Microalgae are microscopic algae found in freshwater and marine systems. There is a huge diversity of micro algae, which represents a huge untapped resource- many species produce unique products like carotenoids, fatty acids, sterols, polymers…. Because of this, microalgae are a promising source of sustainable production for these compounds. But as well as producing these helpful compounds, microalgae can be used as a biofactory to produce biofuel.
Microalgae under a light microscope. (source: wikimedia)
Algae has the potential to be a great renewable source of fuel- being up to 100 times more efficient than other bio-fuel production sources. A lot of work is currently being undertaken with Algae to increase efficiency, and reduce expenses associated with this new technology- but in the future we may well be driving algae-fuelled cars.
References and reading:
Plants that remove contaminants from the Earth- Laboratory medicine 1996
Use of Brassica Plants in the Phytoremediation and Biofumigation Processes
Algal Cell Factories: Approaches, Applications, and Potentials
Image Banner- Images all from wikimedia