The mysteries of how a huge flower that stinks of decaying flesh blooms have been uncovered by scientists.
The so-called “corpse flower”, known more formally as the titan arum or Amorphophallus titanum, typically blooms for only a couple of days and can take years—sometimes over a decade—to bloom again.
Now, according to a new paper in the journal PNAS Nexus, researchers have figured out how the corpse flower warms up its internal temperature—a process known as thermogenesis—just before it blooms, and why it releases its characteristic odor.
The titan arum is native to the rainforests of western Sumatra in Indonesia and is notable for producing a massive, single bloom of a cluster of flowers arranged around a central stalk called a spadix—which can grow up to 12 feet tall—surrounded by a leaf-like “spathe” that resembles a petal.
This plant generally goes between five and seven years between blooms, and suddenly blooms overnight. The bloom releases a pungent, rotting smell composed of sulfur-based compounds, hence its “corpse flower” nickname, which attracts carrion beetles and flies that help with pollination.
“The blooms are rare and also short-lived, so we only get a small window to study these phenomena,” study co-author G. Eric Schaller, a professor of biological sciences at Dartmouth College, said in a statement.
As the spathe unfurls to reveal the spadix within, the spadix heats up by as much as 20 degrees F above the ambient temperature of the plant’s environment and begins to release a cocktail of chemicals including dimethyl trisulfide, dimethyl disulfide, trimethylamine, isovaleric acid, and indole, which smell like cheese, garlic, rotting fish, sweaty socks, and feces, respectively.
Studying the blooms of a 21-year-old corpse flower housed at Dartmouth’s Life Sciences Greenhouse the researchers revealed that the flower also emits a chemical called putrescine, released by rotting dead bodies.
“Putrescine, derived from arginine, was identified as an additional and previously unrecognized component of the titan arum’s odor,” the researchers wrote in the paper.
The researchers took tissue samples from the flower during its bloom to analyze the genes involved in odor generation and thermogenesis.
“This helps us see what genes are being expressed and to see which ones are specifically active when the appendix heats up and sends out odor,” says Schaller.
They found that when blooming began, there was greater expression of genes involved in sulfur transport and metabolism, as well as genes coding for the creation of proteins involved in plant thermogenesis called alternative oxidases, which are counterparts to similar proteins called uncoupling proteins involved in animal heat generation.
The researchers additionally found high levels of an amino acid (protein building block) named methionine, a precursor ingredient to many sulfur-based compounds that smell very bad.
“Our study highlights the dynamic changes that take place in gene expression over just a few days during flowering of the titan arum,” the researchers wrote.
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