Just how big is the world’s biggest plant?
Lesson summary
Hi there everyone, I’m Jeff and you are listening to Plain English, where JR and I help you upgrade your English with current events and trending topics. Today’s lesson is number 479, so that means you can see the full lesson at PlainEnglish.com/479.
Coming up today: At the end of Monday’s lesson, I asked you to imagine the world’s largest plant. Did you picture a tall tree? There’s a grove of trees in Utah in the western United States that was previously thought to be the largest plant in the world. It’s a grove, but all the trees are connected by the same underground root system and it’s a single organism. If you were thinking along those lines, you’re on the right track. In today’s lesson, I’ll tell you about a discovery in Australia—it’s the world’s largest plant and it’s way bigger than anything previously discovered.
In the second half of the lesson, I’ll show you how to use the phrasal verb “look into” and we have a song of the week. Let’s get started.
Australian ribbon weed is world’s largest plant
Scientists in Australia have discovered the world’s largest plant . It belongs to a species of seagrass called Posidonia australis; it’s often called ribbon weed . This species grows in white sand in shallow waters in southern Australia. It grows entirely below the surface of the water. Its leaves are bright green and look like ribbons . This ribbon weed forms in large meadows .
It’s located in Shark Bay off the desert western coast of Australia, about 800 kilometers north of Perth, the nearest city. The area is rich in biodiversity , hosting hundreds of species of fish, birds, and mammals , including dolphins and whales . The world’s biggest fish, the whale shark, spends April and May in Shark Bay.
The plant discovered in Australia covers an astounding area : 200 square kilometers, the same area as 20,000 football fields. To put this in perspective , this is about the size of Brooklyn, New York; Guadalajara, Mexico; or Milan, Italy.
If this plant is so big, you might be asking , how is it that scientists only now discovered it? It turns out that this large area of seagrass has been well-known to scientists for a long time; in fact , teams of biologists have been researching and studying it. But these biologists just recently discovered that it was one plant.
The scientists were looking into the genetic diversity of the seagrass in Shark Bay. The information from that study could be useful for the preservation and restoration of seagrass in other parts of the world. So the researchers from the University of Western Australia collected samples from this large area and created a genetic “fingerprint ” consisting of 18,000 different genetic markers. By studying the genetic makeup of the grasses in this area, they could learn more about what genetic traits make the seagrass in this area so resilient .
After collecting the samples and making a meticulous comparison among all the 18,000 genetic markers , the researchers found…they were all identical . And the only way that could happen is if they were looking at the same organism .
What’s more , if this is all the same plant, then it would have to be extremely old . When we think of old plants, we usually think of tall trees. But this plant doesn’t expand up , it expands out . Plants like this have horizontal roots called rhizomes . The rhizomes stay under the surface and expand outward. Shoots , the vertical parts that poke up above the surface , can sprout up at various points from the rhizomes.
Research into this type of seagrass shows that rhizomes grow at a pace of 35 centimeters per year. Therefore, researchers calculated that the plant must be about 4,500 years old for it to have grown so large.
The plant’s longevity is notable because the region has a harsh climate . The water varies in temperature and salinity throughout the year and the area gets a lot of light, all factors that make it hard for a plant to survive.
There are other interesting points about this plant, too. It has double the number of chromosomes of a typical plant . Most plants—actually most living things— inherit half their chromosomes from their mother and half from their father. This plant inherited one hundred percent of the chromosomes from each parent.
This plant, and others of its species, play a valuable environmental role . Their deep roots prevent erosion of the coastline , they provide shelter for a lot of maritime organisms , and they sequester carbon at a rate much faster than the rainforest . As scientists look for ways to capture carbon from the atmosphere, or to replace the carbon-capturing ability of lost rainforests , the study of seagrasses will be important. And now we know that at least this one species can grow very large indeed .
Nickname needed
Think of everything that has happened in 4,500 years! I mean, there must have been storms , cold years, hot years, droughts , high tides , earthquakes , who knows. And this plant—it’s basically grass, we’re not even talking about a huge tree—this has been growing and growing, 35 more centimeters every year, for 4,500 years.
Imagine being the researcher who was expecting different genetic profiles, and they all came up identical. If that were me, I’d immediately blame myself : I would have thought I’d gotten the samples confused or I mis-labeled something.
There’s only one thing missing from the scientists’ analysis. This plant needs a friendly name ! After four millennia , we need some friendly nickname for this guy, I don’t want to keep calling it “this plant,” how undignified !
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