Aluminum for Plants: Colloidal Properties of Cells
In the plant organism aluminum controls the colloidal properties in the cell and likely activates some dehydrogenases and oxidases.
Aluminum content in plants averages 0.02% (by weight), ranging from 4 mg/kg dry matter in potatoes to 46 mg/kg in turnips.
The toxic effect of aluminum on plants manifests starting from a concentration of 1 mg/L of water, therefore the use of wastewater containing aluminum for irrigating crops is highly undesirable. By forming insoluble compounds with phosphates, aluminum disrupts their absorption by roots, resulting in phosphorus deficiency.
Excess aluminum in the soil leads to deformation of organs: the leaves of most plants curl, white spots appear on them, and the yield of cereal crops grown on acidic soils decreases (about 40% of all cultivated land). When “acid rain” occurs, the toxicity of aluminum increases as it transitions to a soluble state and leaches from clay. This results in the formation of a full spectrum of aberrations in the genomes, chromosomes, and chromatids in the root meristem cells.
Scientists at Cornell University, USA, studying sugar sorghum Sorghum saccharatum (L.) Moench., Poaceae, the fifth most important cereal crop in the world, cloned a previously unknown gene that provides resistance to aluminum from the soil. This gene encodes a membrane transporter that is activated in response to aluminum exposure and facilitates the release of citric acid, which effectively binds toxic ions and prevents their penetration into the roots. Using the new gene, scientists have already created aluminum-resistant plants of thale cress Arabidopsis thaliana (L.) Heynh., Brassicaceae, and soft wheat Triticum aestivum L., Poaceae.
Medicinal plants containing aluminum:
• clubmosses Lycopodiophyta are particularly rich in aluminum – their ash contains up to 5.3% of this metal.