Australian scientists have discovered the largest plant in the world to date. It concerns a hybridization of closely related seagrass species. A single, ancient plant became so huge that it now covers an almost unbelievable 200 square kilometers.
Seagrass Posidonia australis - (Image Credit: Rachel Austin via University of Western Australia)
A research team associated with the University of Western Australia stumbled upon a large area covered by seagrass and found through genetic testing that the entire giant meadow of seagrass is, in fact, one and the same plant.
Poseidon's ribbon weed
The scientists took over 18,000 sample shoots of the seagrass known as Poseidon's ribbon weed (with the scientific name: seagrass Posidonia australis) and found that they were all genetically identical, suggesting they belong to the same organism.
Senior author of the study, evolutionary biologist Dr. Elizabeth Sinclair, stated that she and her colleagues often receive questions concerning how many different plants exist within seagrass meadows, and this time, they used genetic tools to answer it.
Larger than Washington D.C.
Lead author of the study, Jane Edgelo: "The answer blew us away – there was just one!" "That's it; just one plant has expanded over 180 kilometers (covering 200 km2) in Shark Bay''. This makes Poseidon's ribbon weed the biggest known plant in the world
Its surface area is analogous to the size of twenty thousand soccer fields, or slightly larger than Washington D.C.
As mentioned, the giant plant is located in Shark Bay, at the westernmost point of Australia. It lies wholly submerged in shallow, sun-drenched water. Known for its rich and diverse wildlife. The bay has been on the UNES
Shark Bay in Western Australia - (Image Credit: timsimages.uk via Shutterstock / HDR tune by Universal-Sci)
Polyploid
According to the researchers, the seagrass has grown to these epic proportions because the same plant has continuously cloned itself over a period of 4500 years.
Dr. Sinclair explains that one of the things that makes Poseidon's ribbon weed distinctive from other seagrass clones, other than its enormous size, is that it has twice as many chromosomes as its oceanic relatives, meaning it is a polyploid.
Polyploidy is the heritable condition of having more than two full sets of chromosomes. Polyploids are common among plants, in addition to particular groups of amphibians and fish.
Dr. Sinclair explains that whole genome duplication through polyploidy (doubling the number of chromosomes) happens when diploid 'parent' plants hybridize. As a result, the new seedling contains 100% of the genome from each parent instead of sharing the usual 50%.
Polyploid plants can commonly be found in locations with extreme conditions. They are usually sterile but can keep growing if left undisturbed. This particular giant seagrass has done precisely that.
Drone footage of seagrass meadows in Shark Bay - (Image Credit: Philip Schubert via Shutterstock / HDR tune by Universal-Sci)
Further research
It is known that Poseidon's ribbon weed can withstand salinity, bright light, and significant fluctuations in water temperature. The team wants to conduct further research into how the plant could grow for so long in far from ideal conditions.
The team has published their findings in the peer-reviewed science journal Proceedings of the Royal Society B. We listed a link to the paper below for those that would like to check it out.
Sources and further reading:
Extensive polyploid clonality was a successful strategy for seagrass to expand into a newly submerged environment (Proceedings of the Royal Society B)
Polyploidy (nature education)
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