High-tech crops may survive harsh conditions, even…

Plants typically endure long, blazing-hot days to produce the fruits and vegetables that growers desire. The incoming sun’s ultraviolet (UV) rays can be intense — enough to damage some crops. Such plants might benefit from a built-in sunscreen. Now a team of scientists in Australia has stepped in to lend a helping hand.A family of nanoparticles known as metal-organic frameworks, or MOFs, can absorb harmful UV radiation. Joseph Richardson is a nano-engineer. He works in Melbourne at the Australian Research Council Centre of Excellence in Bio-Nano Science and Technology. Some MOFs, he knew, can turn UV rays into other wavelengths — ones that plants could use for photosynthesis. That’s the process by which plants produce food from light.In theory, he could “feed” MOFs to the plants. The problem is, MOFs are too big for plant roots to take up. And cutting open the plants to load them with nanoparticles would damage their stems. So that was not an option. Here a lilyturf plant cutting has been coated with a MOF-coating (luminescent green; top image). That coating protected the plant from harsh UV rays (bottom image), which left an unprotected plant wilted and discolored (arrows). CREDIT: J. RichardsonInstead, he’s leading a research team working to make plants take up the building blocks of MOFs. Their goal: to help plants make their own MOFs. If those MOFs can capture the tissue-damaging UV rays, they might help crops survive tougher climates, both on Earth and in space.It all began when Richardson realized the building blocks used to make MOFs are really small. They are so small that plant roots could slurp them up. His brainstorm: figure out a way to make these building blocks come together inside the plant and grow, on-site, into complete MOFs.With that in mind, his team dissolved the starting materials — metal atoms and special carbon compounds — in water. They then placed plant cuttings into this solution.“To our amazement, these simple materials were taken up by the plant, and grew into full-formed MOFs,” Richardson reports.The scientists engineered these MOFs to fluoresce. They emit an intense green light when irradiated with UV light. This helped confirm the plants built the MOFs on-board. Under UV light, the entire plant fluoresced. Says Richardson, this showed that “MOFs formed in the roots, stems, leaves and other parts of plant.”