If you had to name the world’s largest plant, you’d probably pick some towering, majestic California redwood, right? Well, you’d be wrong – the world’s largest plant is a lot shorter, at least 4,500 years old, and way closer to home.
Researchers at the University of Western Australia (UWA) were trying to map the genetic diversity of the seagrasses in Shark Bay in the state’s north.
However, when they fingerprinted the DNA from Posidonia australis seagrass shoots collected across the area to figure out how many different plants were growing there, says student researcher and study lead Jane Edgeloe, they made a startling discovery.
“The answer blew us away – there was just one! That’s it, just one plant has expanded over 180km in Shark Bay, making it the largest known plant on Earth.
“The existing 200km2 of ribbon weed meadows appear to have expanded from a single, colonising seedling,” she said.
According to UWA evolutionary biologist Dr Elizabeth Sinclair, a senior author of the study, the seagrass in question has twice as many chromosomes as its relatives, making it a “polyploid”.
“Polyploid plants often reside in places with extreme environmental conditions and are often sterile, but can continue to grow if left undisturbed, and this giant seagrass has done just that.
“Even without successful flowering and seed production, it appears to be really resilient, experiencing a wide range of temperatures and salinities plus extreme high light conditions, which together would typically be highly stressful for most plants,” she said.
You’d need one heck of a sea lawnmower to trim that.