A The seagrass bed off the coast of Australia has spent around 4,500 years growing on the ocean floor and is the largest plant discovered to date, according to a study published yesterday (June 1) in Proceedings of the Royal Society B find. Sea grass, which appears to be a hybrid of Poseidon’s ribbon grass (Posidonia australis) and an unknown species, apparently thrived using clonal growth instead of sexual reproduction, Science reports.
Researchers who discovered the gargantuan herbarium initially set out to conduct a genetic survey, hoping to find specimens to replant in restoration projects, The Guardian reports. After analyzing nearly 150 samples from 10 seagrasses between 2012 and 2019, they didn’t see the genetic variation they expected, according to the study. Instead, they found that the shoots they sampled from nine of the meadows all came from the same plant.
“The existing 200 square kilometers of banded weed grasslands appear to have expanded from a single colonizing seedling,” said study co-author Jane Edgeloe, a marine biologist at the University of Australia. -Western. The Guardian.
Normally, ribbongrass has 20 chromosomes, but this giant blanket of seagrass has 40, suggesting it’s actually a cross between the ribbongrass species and an as-yet-unidentified species . “Instead of getting half [of] his mum and half dad genes, he kept them all,” said co-author Elizabeth Sinclair, an evolutionary biologist at the University of Western Australia. The Guardian.
What’s more, rather than dispersing seeds via sexual reproduction, this seagrass appears to clone itself when its rhizomes – underground plant stems – slip and grow outward, spreading its root structure across the seafloor, according to the report. ‘study. Using previous estimates of rhizome growth rates, the researchers were able to estimate the age of the giant clone.
Kathryn McMahon, a coastal biologist at Edith Cowan University who was not involved in the work, says The Guardian that she agrees that the seagrass is from a single specimen and that its estimated age falls within the possible ranges provided.
The researchers found it surprising that a clone survived for such a long time, according to The Guardian. This is because the genetic diversity that accompanies sexual reproduction normally gives it adaptations that allow it to survive a range of environmental conditions. “Plants that are genderless also tend to have reduced genetic diversity, which they normally need to cope with environmental change,” says co-author Martin Breed, an ecologist at Flinders University. The Guardian.
While more research is needed to understand why it thrived for so long, researchers have detected genetic mutations across the grassland’s geographic range that may have contributed to its millennial lifespan, reports The Guardian.