Maize plants detoxify soils from arsenic
Published: Tuesday, Apr 2nd 2024, 10:10
Zurück zu Live Feed
Maize plants defend themselves against the toxic substance arsenic. Their roots release a kind of antidote into the soil, as Swiss researchers have shown in a new study. As a result, they not only absorb less arsenic, but also detoxify the soil.
This knowledge could be used to breed maize plants that absorb particularly little arsenic, the University of Basel announced on Monday.
Arsenic is a toxic semi-metal. Excessive exposure to arsenic is carcinogenic and can lead to neurological impairments. The toxic substance occurs naturally in many soils and bodies of water, while others are contaminated by mining or agriculture, which used to use arsenic as an insecticide. Countries such as Bangladesh, Vietnam and China are particularly affected. But there are also individual hotspots in Switzerland where arsenic naturally occurs in above-average concentrations, as the university emphasized - for example in the soil of Liesberg BL.
Plants confuse poison with nutrient
Plants confuse the toxic substance with phosphorus, an important nutrient. As the two substances are chemically similar, arsenic is absorbed by phosphorus transport channels in the roots of the plants.
In their new study, which appeared in the journal "Pnas", the researchers led by Klaus Schläppi from the University of Basel and Matthias Erb from the University of Bern have now shown that maize defends itself against arsenic by means of so-called benzoxazinoids. The maize plants release this substance into the soil through their roots.
"There were indications that maize absorbs less arsenic compared to other plant species," said Schläppi in the press release. To find out why this is the case, the researchers planted wild maize varieties and maize plants with a genetic defect that prevents the production of benzoxazinodia on arsenic-containing and arsenic-free soils.
Antidote lasts a long time
It was found that the wild-type maize grew significantly better on arsenic-rich soils than the maize that did not secrete the antidote. In addition, the protective effect of the antidote released by the maize plants lasted a long time: A second generation of maize also benefited from the antidote released by the first.
According to the researchers, it is not yet fully understood exactly how this defense mechanism works. They suspect that the benzoxazinoids, i.e. the antidote, convert the toxic arsenic in such a way that it can no longer be absorbed by the roots.
©Keystone/SDA
German 
English 
French 
Spanish 
Arabic