A new breed of ‘super plants’ could one day be used to grow a range of different nanomaterials and food on distant worlds, according to scientists.
Researchers from the University of Melbourne (UM) have turned to an age-old florist’s trick that allows plants to do rather unnatural things – in this case, grow powerful nanomaterials.
Due to reveal their research later today (3 April) at a meeting of the American Chemical Society, the scientists have shown it is possible for metal-organic frameworks (MOFs) to be absorbed by plants through their stems, in the same way that florists have used dye-coloured water to create fantastic colours in flower petals.
In doing so, they believe these augmented, hybrid plants could potentially perform a number of new functions, such as sensing chemicals or harvesting light more efficiently.
Because of their extensive vascular networks, plants readily absorb water and molecules that can be dissolved in fluids. However, much larger materials, such as MOFs, have previously been shown to be much harder to absorb in the plant’s roots.
MOFs – which consist of metal ions or clusters linked to organic molecules – act like a sponge that can soak up, store and release other molecules. Thousands of different MOFs have been created so far, with applications ranging from hydrogen fuel storage to absorbing greenhouse gases, but adding them to plants could give them new unnatural abilities.
To get past the size barrier, the UM researchers tested to see whether the precursor of MOFs would be small enough to be absorbed by the plants, and then converted into finished nanomaterials. To do this, they added metal salts and organic linkers to water, and then placed cuttings or intact plants into the solution.
Sure enough, the plants absorbed these MOF precursors, with two different types of fluorescent MOF crystals growing out of them. In a proof-of-concept experiment, MOF-producing lotus plant clippings detected small concentrations of acetone in water, as shown by a decrease in fluorescence of the materials.
MOFs could also be used as a coating for the same plants to help them convert harmful ultraviolet (UV) rays into more useful photosynthesis.
“As we contemplate growing crops in space or on Mars, where you don’t have an atmosphere and are bombarded by UV rays, something like this could be helpful,” said Joseph Richardson, lead researcher on the project. “That’s because it not only protects the plants from the UV rays, but it also turns them into useful energy. Especially as you get farther away from the sun, it’s harder to capture all of the light you’d need for photosynthesis.”
The researchers are now working with plant biologists to see the effects of MOFs on plant growth, but so far they haven’t seen any toxicity of the nanomaterials. The breakthrough could even be used to help plants grow better, with potentially major applications in agriculture, the researchers added.