Essay Sample on Titan Arum: Why Does It Smell So Bad?

The Amorphophallus titanum, more commonly known as the titan arum has attracted scientists for centuries since its discovery in 1878. As a species primarily found in and native to the Sumatran islands, it is considered by many to be an endemic species (Arianto et al., 2018). The plant is easily identified by its dark purple and green colors as well as having the largest inflorescence in the world (Shirasu et al., 2010). A. titanum, of family Araceae, blooms once in a several year period with about five years between flowerings. Perhaps the most recognizable characteristic of the titan arum is its distinctively nauseating smell. This rotting animal-like odor emitted gave the titan arum yet another name: the corpse flower (Shirasu et al., 2010). Looking at the A. titanum from many biological levels including biochemical, structural, and evolutionary gives a clearer understanding as to why the corpse flower smells so bad. 

The chemical identity of the compounds present during the flowering of the titan arum explains the smell on a microscopic level. The scent emitted by the A. titanum, is composed of a total of 25 compounds (Raman et al., 2017). Dimethyl disulfide [DMDS] was originally thought to be the main component of the smell; however, as technology progressed, it was found that Dimethyl trisulfide [DMTS] is the biggest contributor to the odor using gas chromatography-mass spectrometry-olfactometry (Shirasu et al., 2010). Other key compounds included aliphatic compounds, meaning structures of carbon and hydrogen bound together in straight lines without loops. Specifically, tridecane was most abundant after DMTS and DMDS (Heiduk et al., 2010). Each class of compound was found to add a layer of complexity to the smell. DMTS and DMDS contributed a sulfur-like scent that was most abrasive for the human nose. Trimethylamine, released at the end of flowering, and isovaleric acid add a rotten fish and valerian odor respectively. Finally, aromatic compounds such as benzaldehyde, benzyl alcohol, and methyl-based compounds give a fruity or green smell (Shirasu et al., 2010). 

While looking through a biochemical lens helps to determine what the odor is composed of, the structure of the A. titanum clarifies where the scent comes from and how it is produced. Key points of anatomy must be identified to understand this. The spathe of the plant, the purple and green, leafy outer shell covers the base of the plant. The tan column, or spadix rising from the spathe is composed of thousands of tiny individual flowers. Finally, the male and female flowers are separated into groups along either side of the spadix (Raman et al., 2017). During a short flowering period of only two days, the spathe loosens allowing the female flowers to open on the first night followed by the male flowers opening on the second night. The opening and closing of the spathe is influenced by sunlight, so it does not close again until the third day (Korotkova et al., 2009). The odor itself emits from the lobe tips and spathe of the flower (Heiduk et al., 2010). On a cellular level, the spathe has very few oils in its structure. Oil dissolves odor, thus the strong scent (Raman et al., 2017). The smell is produced when the spathe is full open, so it begins the late evening of the first day (Shirasu et al., 2010). It is strongest during the female flowering phase, indicating that most of the scent detected later must be residual (Korotkova et al., 2009). 

Like many others, A. titanum attracts pollinators by visual and olfactory cues, but there is more emphasis scents than visual aspects for the titan arum (Heiduk et al., 2010). The main pollinators of the plant are five species of flies, beetles, and moths. The scent mimics that of rotting animals and fermented food, thus tricking flies into pollinating it (Shirasu et al., 2010). The thermogenesis, or internal heating, of the spadix also contributes to pollinator attraction (Korotkova et al., 2009). A. titanum has a very short flowering period of only two days, so it needs to effectively attract pollinators (Raman et al., 2017). If the plant is successful, the smell becomes sweeter as time progresses, acting as a reward for the insects (Steenhuisen et al., 2010). The changing scent leads to efficient learning for pollinators, promotes and adds variety in the insects attracted to the flower. Specific pollinators depend on scent composition; flies and moths are attracted to the DMDS, while aromatic and aliphatic compounds attract beetles. 

The corpse flower’s distinctive scent can be explained by the chemical compounds present and the structure of the plant. Together, they produce a smell that effectively attracts pollinators during the A. titanium’s short flowering period. Understanding this integrative perspective is key to answering the question that baffled scientists for centuries: why does the Amorphophallus titanum smell so bad?