The titan arum, aptly nicknamed the “corpse flower,” is notorious for its infrequent blooms and overwhelming stench of rotting flesh. This intriguing plant, which boasts a towering spadix that can reach heights of 12 feet (3.7 meters), has long fascinated scientists and the public alike. Now, a new study published in PNAS Nexus has finally uncovered the molecular secrets behind its pungent aroma and unique warming ability.
The titan arum’s bloom is a rare and fleeting event, occurring only every five to seven years. When it does bloom, a petal-like structure called the spathe unwraps from the base of the spadix, revealing a cluster of tiny flowers. This is accompanied by a remarkable process called thermogenesis, where the spadix heats up, sometimes becoming up to 20 degrees Fahrenheit warmer than the surrounding air. This heat intensifies the release of volatile compounds, creating the plant’s distinctive odor.
Researchers at Dartmouth College, led by molecular biologist G. Eric Schaller, investigated the molecular mechanisms driving these phenomena. They studied a 21-year-old titan arum named Morphy, housed in Dartmouth’s Life Sciences Greenhouse, collecting tissue samples during several blooming periods. Through RNA sequencing, they identified the genes active during thermogenesis and odor production.
The analysis revealed increased expression of genes related to sulfur transport, sulfur metabolism, and heat production during the early stages of blooming. This suggested a link between sulfur compounds and the plant’s characteristic smell.
Further investigation using mass spectrometry, a technique that identifies chemical substances, confirmed the presence of elevated methionine levels in the early bloom samples. Methionine, a sulfur-containing amino acid, is a precursor to volatile sulfur compounds, which readily vaporize when heated, contributing to the pungent odor.
The researchers also made a surprising discovery. In samples from the spathe, they found elevated levels of an amino acid that serves as a precursor to putrescine. Putrescine is a compound known for its association with the smell of decaying flesh. This marks the first time putrescine has been identified in the titan arum, providing a key piece of the puzzle in understanding the plant’s unique aroma.
This study provides the first molecular-level insights into the corpse flower’s thermogenesis and odor production, explaining the infrequent but memorable “murder mystery” scent experienced in greenhouses around the world. Schaller and his team plan to continue their research, focusing on the triggers that initiate blooming and exploring the potential for synchronized blooming among multiple plants.
This groundbreaking research not only reveals the secrets of the corpse flower’s stench but also contributes to our understanding of thermogenesis and volatile compound production in plants, opening up new avenues for future research.
