Wheat and couch grass can extract toxic metals from contaminated soils

August 10, 2020

Irina Shtangeeva is a researcher at the Department of Soil Science and Soil Ecology, St Petersburg University. She has studied the ability of wheat and couch grass to accumulate toxic substances. Both plants were capable of absorbing various chemical elements from contaminated soils. Although the plants were able to accumulate high concentrations of toxicants, they could survive under negative environmental conditions. Interestingly, the plants accumulated toxicants in the aerial parts thus removing them from contaminated soils. This ability of couch grass and wheat to phytoextract toxic metals can be used for effective cleaning of soils.

At present, ecologists often use phytoremediation method for soil decontamination and wastewater treatment. It is a complex of remedial measures in which the key role is played by green plants. Phytoextraction is one of the directions of this method, which makes it possible to remove certain toxic trace elements from contaminated soils using plants-hyperaccumulators. This method is relatively inexpensive. It also does not destroy the soil. However, usually one such a plant is able to accumulate only one element in its aerial parts.

'In my opinion, the search for new plants that can accumulate one metal is a dead-end job,' says Irina Shtangeeva, researcher at the Department of Soil Science and Soil Ecology, St Petersburg University. 'Soil is usually contaminated with more than one toxic trace element. For the successful use of the phytoremediation method, it is therefore important to find such plants that will accumulate a large amount of various toxic elements in the aerial parts without significant damage to plant development.'

The experiments have shown that wheat and couch grass can be promising candidates for the aims of soil remediation. Irina Shtangeeva found that wheat is able to survive in the most adverse conditions and it also efficiently accumulates various substances from the soil. Couch grass is one of the most common weeds in vegetable gardens. It also grows well near the streets with heavy traffic. It is distinguished by its vitality and the ability to accumulate a large amount of different trace elements.

'Nowadays, you can find a lot of research about the plants capable of accumulating cadmium, nickel, selenium and some other trace elements, the so-called heavy metals. However, many other potentially toxic metals and metalloids are not well-studied,' says Irina Shtangeeva. 'That is why I have chosen for my work "unpopular" trace elements that are still little known in the context of phytoremediation: bromine, europium, scandium, thorium, and uranium. Wheat and couch grass have shown the ability to efficiently accumulate all these trace elements simultaneously. As a result, their content in the contaminated soil decreases.'

What happens to the plants after they have absorbed metals from the soil? As Irina Shtangeeva explains, they can be used in the future. In Germany, Switzerland, the USA and some other countries, there are commercial companies that accept these plants for processing and extract the trace elements from them for use in industry.

The scientist emphasises that it is also important to take into account the specific time of cutting the plants. As her other studies show, plants are affected by the circadian rhythm. The concentration of metals in plants can change with the time of day. For example, plants that were collected at noon can contain more contaminants than plants collected in the morning or evening.

Another important factor that helps to make the phytoextraction process more efficient is the use of bacteria. Experiments of Irina Shtangeeva demonstrated that seeds treated with Cellulomonas bacteria allow plants accumulating more metals from contaminated soils. It is quite likely that the bacteria are able to transfer metals into a more available for plants form.
-end-


St. Petersburg State University

Related Bacteria Articles from Brightsurf:

Siblings can also differ from one another in bacteria
A research team from the University of Tübingen and the German Center for Infection Research (DZIF) is investigating how pathogens influence the immune response of their host with genetic variation.

How bacteria fertilize soya
Soya and clover have their very own fertiliser factories in their roots, where bacteria manufacture ammonium, which is crucial for plant growth.

Bacteria might help other bacteria to tolerate antibiotics better
A new paper by the Dynamical Systems Biology lab at UPF shows that the response by bacteria to antibiotics may depend on other species of bacteria they live with, in such a way that some bacteria may make others more tolerant to antibiotics.

Two-faced bacteria
The gut microbiome, which is a collection of numerous beneficial bacteria species, is key to our overall well-being and good health.

Microcensus in bacteria
Bacillus subtilis can determine proportions of different groups within a mixed population.

Right beneath the skin we all have the same bacteria
In the dermis skin layer, the same bacteria are found across age and gender.

Bacteria must be 'stressed out' to divide
Bacterial cell division is controlled by both enzymatic activity and mechanical forces, which work together to control its timing and location, a new study from EPFL finds.

How bees live with bacteria
More than 90 percent of all bee species are not organized in colonies, but fight their way through life alone.

The bacteria building your baby
Australian researchers have laid to rest a longstanding controversy: is the womb sterile?

Hopping bacteria
Scientists have long known that key models of bacterial movement in real-world conditions are flawed.

Read More: Bacteria News and Bacteria Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.