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Scientists Blown Away by World’s Largest Plant – Stretching 112 Miles in Western Australia’s Shark Bay

Ribbon weed, Posidonia australis, meadow in Shark Bay, Western Australia. Credit: Rachel Austin, University of Western Australia

Scientists were investigating meadows of ribbon weed seagrass using DNADNA, or deoxyribonucleic acid, is a molecule composed of two long strands of nucleotides that coil around each other to form a double helix. It is the hereditary material in humans and almost all other organisms that carries genetic instructions for development, functioning, growth, and reproduction. Nearly every cell in a person’s body has the same DNA. Most DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria (where it is called mitochondrial DNA or mtDNA).” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>DNA analysis. The shocking results blew them away; the 18,000 DNA markers they analyzed in Shark Bay World Heritage Area, in Western Australia showed a single plant expanded to stretch 112 miles. This makes it the world’s largest known plant.

Somehow this single seedling grew to cover an area of 77 square miles, stretching through waters that are quite different in temperature and salinity. Based on its size and growth rate, the researchers estimate that it is 4,500 years old.

Next time you go diving or snorkeling, have a close look at those wondrously long, bright green ribbons, waving with the ebb and flow of water. They are seagrasses – marine plants which produce flowers, fruit, and seedlings annually, like their land-based relatives.

These underwater seagrass meadows grow in two ways: by sexual reproduction, which helps them generate new gene combinations and genetic diversity, and also by extending their rhizomes, the underground stems from which roots and shoots emerge.

To find out how many different individual plants are growing in a seagrass meadow, you have to test their DNA. We did this for meadows of ribbon weed seagrass called Posidonia australis in the shallow sun-drenched waters of the Shark Bay World Heritage Area, in Western Australia.

The result blew us away: it was all one plant. One single plant has expanded over a stretch of 180 km (112 miles) making it the largest known plant on Earth.

We collected shoot samples from ten seagrass meadows from across Shark Bay, in waters where the salt levels range from normal ocean salinity to almost twice as salty. In all samples, we studied 18,000 genetic markers to show that 200 km² (77 miles²) of ribbon weed meadows expanded from a single, colonizing seedling.

Source: SciTechDaily