巨型杂交风滚草在加利福尼亚蔓延

巨型杂交风滚草在加利福尼亚蔓延

California has enough to worry about on the invasive species front, thank you very much, but it's now also home to a monster hybrid tumbleweed.

加州在入侵物种方面有足够的担忧，非常感谢，但现在它也是一种巨型杂交风滚草的家园。

Researchers at the University of California, Riverside, have discovered that two large invasive species of tumbleweed have joined together to create a new invasive species of tumbleweed, and it's spreading quickly. They recently took a closer look at this large tumbleweed to see why it was thriving.

加州大学河滨分校(University of California, Riverside)的研究人员发现，两种大型入侵物种的风滚草结合在一起，形成了一种新的入侵物种——风滚草。最近，他们仔细观察了这棵巨大的风滚草，想知道它为什么会茁壮成长。

Now that's a tumbleweed. A truck bed-sized specimen collected by Shana R. Welles in Riverside, California. (Photo: University of California, Riverside)

They found that the species, Salsola ryanii, is much larger than either of its parent plants, which can grow up to 6 feet tall. Findings from their study published in AoB Plants show that the tumbleweed likely grows faster and stronger because it has two pairs of its of its parents' chromosomes.

他们发现Salsola ryanii这个物种比它的任何一种母体植物都要大得多，它们可以长到6英尺高。他们发表在《AoB Plants》上的研究结果表明，风滚草可能生长得更快、更强壮，因为它有两对它父母的染色体。

Finding the tumbleweed

寻找风滚草

The monster tumbleweed was first documented by scientists with the California Department of Food and Agriculture back in 2002 in two areas of the state's Central Valley. The plant, a hybridization of Salsola australis and Salsola tragus, was found to have spread to a third area of the Central Valley in 2009.

2002年，加州食品和农业部的科学家在加州中央山谷的两个地区首次记录了这种巨大的风滚草。2009年，人们发现这种植物已经蔓延到中央山谷的第三个地区。

As UC Riverside explains, the "problematic" Salsola tragus, believed to have the most rapid spread of any introduced species, is found in 48 states. It first arrived on American shores in the late 19th century aboard contaminated shipments of flax seed from Russia.

正如加州大学河滨分校(UC Riverside)所解释的那样，在48个州发现了被认为是所有外来物种中传播速度最快的“有问题的”红腹角雉(Salsola tragus)。它第一次到达美国海岸是在19世纪末，当时是从俄罗斯运来的受到污染的亚麻籽。

'The potential to be a problematic invasive'

“潜在的有问题的侵入性”

But back to the unholy union of these two tumbleweeds. In 2012, researchers from UC Riverside found that Salsola ryanii had indeed spread well beyond the confines of the Central Valley to the San Francisco Bay Area and Ventura County, northwest of Los Angeles, in just over a decade.

回到这两株风滚草的邪恶结合上来。2012年，加州大学河滨分校(UC Riverside)的研究人员发现，Salsola ryanii的确在短短十多年的时间里，已经远远超出了中央谷地的范围，蔓延到了旧金山湾区(San Francisco Bay Area)和洛杉矶西北部的文图拉县(Ventura County)。

Welles notes that average folks won't be able to differentiate Salsola ryanii from the two species of tumbleweed that spawned it. The hybridized plant was identified via DNA testing of plant samples collected at 53 different sites. Of these sites, Salsola ryanii was present at 15 — or 28% — of them, contradicting earlier notions that it would not spread beyond isolated areas of the Central Valley.

威尔斯指出，一般人将无法区分Salsola ryanii和产生它的两种风滚草。通过对53个不同位点的植物标本进行DNA检测，鉴定出杂交植株。在这些遗址中，Salsola ryanii出现在其中的15个，即28%，这与之前认为它不会扩散到中央山谷的孤立地区的观点相矛盾。

While Welles concludes her findings in a most ominous manner — "We are not aware of any plant neospecies whose range spontaneously experienced such a dramatic expansion. Salsola ryanii has every indication of being just as invasive as its highly invasive parents" — at least she and her colleagues have a sense of humor about it.

尽管威尔斯以一种极为不祥的方式总结了她的发现——“我们不知道有任何一种新物种的范围能自发地经历如此剧烈的扩张。猪毛菜ryanii种种迹象表明已是一样入侵其高度侵袭性的父母”——至少她和她的同事有幽默感。