Imagine strolling through a street just after sunset and seeing your path lit – not by the orange glow of a sodium streetlamp – but by a row of glowing, multi-coloured palm trees.
A scene like this may soon become a reality after scientists in China succeeded in making succulents, called Echeveria “Mebina”, radiate in hues of red, blue and green.
They did this by injecting the plants with strontium aluminate, the same substance used in glow-in-the-dark toys that absorbs light and gradually releases it over time.
“Picture the world of Avatar, where glowing plants light up an entire ecosystem… Imagine glowing trees replacing streetlights,” Dr Shuting Liu, a researcher at South China Agricultural University in Guangzhou and co-author of a study published in the journal Matter on Aug 27, told CNN.
Their approach deviates from the traditional gene-editing technique that scientists have been using since 2018 to make glow-in-the-dark plants. Gene editing can make plants luminesce but only in their natural green colour.
Dr Liu told CNN her team’s goal was to “integrate multicolour, long-afterglow materials with plants”.
What she and her fellow researchers sought was “essentially, a light charged, living plant lamp”.
Succulents, it turns out, are nature’s perfect vessels for such luminescence, as their leaves are laced with neat little channels that help the glow spread evenly.
To demonstrate the practical application of their work, the researchers created a wall of 56 modified succulents that emitted enough light to illuminate text, images and a person 10cm away.
The glow rivals that of a candle or a small night light.
Once injected with strontium aluminate and placed under direct sunlight for a couple of minutes, the plants continued to glow for up to two hours.
Though the brightness gradually weakened, the plants could be “recharged” by again placing them under direct sunlight.
“It was really unexpected,” Dr Liu said. “The particles diffused in just seconds, and the entire succulent leaf glowed.”
She said the succulents can be recharged for up to 25 days. Even leaves that have wilted continued to emit light under ultraviolet stimulation.
She said while strontium aluminate can break down in plants and damage tissue, her team has developed a chemical coating that acts as a protective barrier.
A wall of 56 glow-in-the-dark succulents built by researchers in China produces enough light to illuminate a person 10cm away.
PHOTO: DR SHUTING LIU/MATTER
Other scientists, though, think more work needs to be done before glow-in-the-dark plants can have safe, real-world applications.
“I like the paper, it’s fun. But I think it’s a little beyond current technology, and it might be beyond what plants can bear,” Dr John Carr, a professor of plant sciences at the University of Cambridge, who was not involved in the study, told CNN.
“Because of the limited amount of energy that these plants can emit, I don’t really see them as streetlights anytime soon,” he said.
Dr Liu acknowledged that her team has yet to ascertain whether strontium aluminate will make plants toxic when eaten, posing hazards to domestic animals and wildlife.
But she remains positive.
“Looking ahead, if we can significantly enhance the brightness and extend the duration of luminescence – and once safety is conclusively demonstrated – we could envision gardens or public spaces being softly illuminated at night by glowing plants,” she said.
Scientific researchPlantsScienceUrbanisation and urban planningChina
