Monster Tumbleweed Invades US

first_imgA hybrid species of giant tumbleweed once expected to go extinct is alive and well—and growing.Salsola ryanii, according to a study from the University of California Riverside, develops more “vigorously” than its parent plants thanks to a double set of their chromosomes.“[This] is a nasty species replacing other nasty species of tumbleweed in the US,” study co-author and UCR professor Norman Ellstrand said in a statement. “It’s healthier than earlier versions, and now we know why.”Humans are diploid organisms, meaning we are conceived with one set each of male and female chromosomes.Plants, on the other hand, can produce triploid offspring—with three sets of chromosomes—that survive but are unable to reproduce themselves.Then there’s hybrid plants, like Salsola ryanii, which manage to obtain two copies from Mom and two copies from Dad—also known as polyploidy.Domesticated peanuts, for instance, have four sets of chromosomes; wheat has six.Scientists have long assumed there must be some kind of evolutionary advantage to having multiple sets of chromosomes.“Typically, when something is new, and it’s the only one of its kind, that’s a disadvantage,” according to co-author Shana Welles, a former UCR graduate student. “There’s nobody exactly like you to mate with.”The benefit, it turns out, is that the hybrid plant grows more robustly than either of its parents.Despite its frequent use as a symbol of humor, tumbleweed is no joke.Some species are serious weeds that absorb moisture from soil and promote wind erosion.Others—especially if thorny—can knot themselves together until they form piles that no longer roll. These physical barriers may block roadways or even trap vehicles or buildings and their occupants inside a massive fire hazard.Study co-author Shana Welles discovered this tumbleweed specimen in Riverside (via University of California, Riverside)Be afraid. Be very afraid: More resolute than its progenitors—which are invasive in 48 states—Salsola ryanii’s range is likely to continue spreading. Climate change could also increase its territory takeover.This species of tumbleweed tends to grow on the later side of winter, and is often “one of the only things that’s still green in later summer,” Welles said.“They may be well positioned to take advantage of summer rains if climate changes make those more prevalent,” she added.Given its penchant for mayhem, the more we know about Salsola ryanii the better.Ellstrand believes any knowledge of this hybrid hoodlum could be important for helping to suppress it.“An ounce of prevention is a pound of cure,” he said.The team’s findings were published recently in the journal AoB Plants.More on, Invasive Lizard Finally Captured in FloridaInvasive Rabbits Ruined Ecosystem of Isolated IslandsInvasive Pest Tunicate Finds New Role as Sustainable Materiallast_img

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