In order to plant enhance plant growth, a team of researchers has suggested that purified single-walled carbon nanotubes dispersed in water improved the early growth of wheatgrass, but in presence of contaminants, those same nanotubes could do great harm.
Researcher Andrew Barron from Rice University in Houston, Texas, US grew wheatgrass in a hydroponic garden to test the potential toxicity of nanoparticles on the plant.
They found that one type of particle dispersed in water helped the plant grow bigger and faster.
The researchers planted wheatgrass seeds in multiple replicates in cotton wool and fed them with dispersions that contained raw single-walled or multi-walled nanotubes, purified single-walled nanotubes or iron oxide nanoparticles that mimicked leftover catalyst often attached to nanotubes.
The solutions were either water or tetrahydrofuran (THF) - an industrial solvent.
After eight days, they showed that purified single-walled nanotubes in water enhanced the germination rate and shoot growth of wheatgrass, which grew an average of 13 percent larger than plants in plain water.
However, purified single-walled nanotubes in THF retarded plant development by 45 percent compared to single-walled nanotubes in water, suggesting the nanotubes act as a carrier for the toxic substance.
Barron said that if single-walled nanotubes combine with organic pollutants like pesticides, industrial chemicals or solvents in the environment, then they may concentrate and immobilise the toxins and enhance their uptake by plants.
The research appears in the journal Environmental Science: Nano.