First discovery of bilirubin in a flower announced

September 8, 2010, American Society for Horticultural Science
Bilirubin has been discovered in the beautiful and iconic Bird of Paradise flower. Credit: Photo by David Lee

A research team led by Cary Pirone from the Department of Biological Sciences at Florida International University has identified bilirubin in the popular Bird of Paradise plant. The breakthrough study, published in the September 2010 issue of the American Society for Horticultural Science's journal HortScience, provides new insights into color production in this iconic tropical plant.

Previously thought to be an "animal-only" , is best known as the yellowish hue associated with bruises and jaundice sufferers. In 2009 the FIU researchers found bilirubin in the arils of Strelitzia nicolai, the white Bird of Paradise tree. The incredible discovery—that bilirubin exists in both plants and animals—put Pirone's research on the scientific map. The current study expands the original research and reveals new insights into the presence of animal pigment in flowers. Advisor David Lee credits Pirone for her persistence and scientific acumen. "Cary has made a remarkable discovery", he noted, adding that it was Pirone's persistence and curiosity that persuaded colleagues that she was on the right track.

Strelitzia reginae Aiton, the Bird of Paradise plant, is known for its vibrant orange and blue inflorescences. Native to South Africa, it is widely cultivated in warm temperate and tropical regions. Aside from the widely recognized shape of its flower, which resembles the head of a bird, Strelitzia reginae is also admired for its brilliant floral coloration. In contrast to its showy flowers, the fruit of the Bird of Paradise is pale and partially obscured by the bract during development. When it matures, however, the capsule breaks open to reveal intensely colored orange arillate seeds. Remarkably, the distinct aril color can remain unchanged for decades after the plant dies.

These are the arils of the Bird of Paradise flower, Strelitzia reginae. The capsule is about 1 3/4" wide when open. Credit: Photo by Tom DeFanti

Using high-performance liquid chromatography (HPLC) and HPLC/electrospray ionization-tandem mass spectrometry, the research team discovered bilirubin to be the primary aril pigment of Strelitzia reginae and found low concentrations of bilirubin in the plant's sepals. In mature aril tissue, bilirubin was present as granular bodies irregularly distributed throughout the cell. In mature sepal tissue, the researchers observed elongate structures that were previously identified as containing carotenoids.

"This research is the first discovery of bilirubin in a flower; it verifies the presence of bilirubin in a plant species other than Strelitzia nicolai. With further research on the function, distribution, and synthesis of bilirubin in plants, the information may be useful for practical applications such as the manipulation of color through breeding and genetics", the researchers concluded.

The findings will likely have broad appeal among flower lovers, observed Lee. "When you discover something this significant about something this familiar (the Bird of Paradise flower), the story has power".

Explore further: First discovery of 'animals-only' pigment bilirubin in plants

More information: The complete study and abstract are available on the ASHS HortScience electronic journal web site: … t/abstract/45/9/1411

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Sep 08, 2010
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4.8 / 5 (5) Sep 08, 2010
I am wondering why this is such breathtaking news. Or, to put it another way, so what? Lots of chemicals are found in both plants and animals, lots more developed independently in different species of plants at different times. This only shows that bilirubin is good for what it does.
5 / 5 (1) Sep 08, 2010
Nope, convergent evolution results as a common solution of the same adaptation problem. Plants do not share any common adaptation problem with animals here - until you prove the opposite.

Pigmentation for the purposes of reproduction.
1 / 5 (1) Sep 09, 2010
Orchids attracts insects to make them attractable for example hummingbirds who won't eat always the hole insects, mutes epiphyter.
not rated yet Sep 09, 2010
Pigmentation for the purposes of reproduction.
Which purpose? To attract the pollinators?
In the case of the flower, yes.
2.3 / 5 (3) Sep 09, 2010
In the case of the flower, yes.

But not in the case of animals, so it's NOT an example of convergent evolution.
not rated yet Sep 09, 2010
In the case of the flower, yes.

But not in the case of animals, so it's NOT an example of convergent evolution.

Many birds use their brilliant plumage to attract mates for purposes of reproduction, same with lizards, fish, etc.

It is a prime example of convergent evolution.
not rated yet Sep 09, 2010
If you check out some UV images of this flower you will have a better appreciation of what a pollinating insect might see.
not rated yet Sep 09, 2010
Mates and pollinators are a functional form of intercourse.
Bright yellow in multiple species is provided via bilirubin.
you're arguing just to argue. Stop that.
not rated yet Sep 09, 2010
The only common adaptation here is to use the same dye to make the same color birilubin seems to be a good dye so it is used.

It has to be able to be manufactured by the plant or animal that uses it and has to be something not too complicated or it would never have been selected for. There are probably a number of close chemical variations to birilubin that are good for something as well.

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