African fruit 'brightest' thing in nature but does not use pigment to create its extraordinary colour

Sep 10, 2012
Pollia condensata fruit. Credit: Silvia Vignolini

(Phys.org)—The 'brightest' thing in nature, the Pollia condensata fruit, does not get its blue colour from pigment but instead uses structural colour – a method of reflecting light of particular wavelengths- new research reveals. The study was published today in the journal PNAS.

Most colours around us are the result of pigments.  However, a few examples in nature – including the , the scarab beetle and now the Pollia condensata fruit – use structural colour as well.

Fruits are made of cells, each of which is surrounded by a cell wall containing . However, the researchers found that in the Pollia condensata fruit the cellulose is laid down in layers, forming a chiral (asymmetrical) structure that is able to interact with light and provide selective reflection of only a specific colour.  As a result of this unique structure, it reflects predominately blue light.

Credit: Silvia Vignolini

The scientists also discovered that each individual cell generates colour independently, producing a pixelated or pointillist effect (like those in the paintings of Seurat). This colour is produced by the reflection of light of particular wavelengths from layers of cellulose in the cell wall. The thickness of the layers determines which is reflected. As a result, some cells have thinner layers and reflect blue; others have thicker layers and reflect green or red.

The researchers believe that the plants invest in the complicated colouring structure as a mechanism for . Although the Pollia fruit does not provide any , birds are attracted to its bright colouring – possibly as a means of decorating their nests or impressing their mates.

Dr Beverley Glover from the University of Cambridge's Department of , who jointly led the research, said: "This obscure little plant has hit on a fantastic way of making an irresistible shiny, sparkly, multi-coloured, iridescent signal to every bird in the vicinity, without wasting any of its precious photosynthetic reserves on bird food. Evolution is very smart!"

Credit: Silvia Vignolini

Because of how it is created, the colour of the Pollia condensata fruit does not fade.  The researchers found that samples of the fruit in herbarium collections dating back to the 19th century were as colourful and shiny as ones grown today.

Dr Silvia Vignolini, lead author on the paper from the University of Cambridge's Department of Physics, said: "By taking inspiration from nature, it is possible to obtain smart multifunctional materials using sustainable routes with abundant and cheap materials like cellulose.

"We believe that using cellulose to create coloured materials can lead to many industrial applications. As an example, edible cellulose-based nanostructures with structural colour can be used as substitutes for toxic dyes and colorants in food. Moreover, the fact that the processes involved in cellulose extraction and manipulation are already used in the paper industry facilitates the use of such materials for industrial applications such as security labelling or cosmetics."

Explore further: Nest-building in finches is a learning process developed through experience

More information: "Pointillist structural color in Pollia fruit," by Silvia Vignolini et al. www.pnas.org/cgi/doi/10.1073/pnas.1210105109

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User comments : 29

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chardo137
4.9 / 5 (8) Sep 10, 2012
Bluebirds and Hummingbirds also use a similar method to provide color.
Thadieus
3.2 / 5 (5) Sep 10, 2012
I wonder if you eat a lot of Pollia condensata fruit your stool will glow blue.
It happens with carrots.
xen_uno
4.4 / 5 (14) Sep 10, 2012
Evolution doesn't have "intelligence" per se, it merely adheres to physical law and probability. The bible wasn't written by any "creator", nor were humans instructed to do so. It was written by a dozen or so starving peasants under the rule of an oppressive Roman regime, using the most popular prophet of the time, Jesus, as subject matter. The authors embellished his life and added time honored stories passed down thru the generations. The 10 commandments of the bible (the only worthy part) is not god sent ... most DECENT humans were born with keen sense of it. I was and I've despised Religion Inc for years.

About this "creator" ... have you read the Old Testament lately? If indeed His own words, it is riddled with hate, vengeance, barbarism, racism, arrogance, egotistical worshiping, etc. So brutal in fact that humans later re-wrote it to read as the New Testament, toned down and sugar coated to be more appealing to the masses.
Salus
4.1 / 5 (10) Sep 10, 2012
Butterflies also use a similar method.

But no, Evolution is NOT very smart! If fact, it is very dumb and unscientific.

Our Creator is very smart. Smarter than any of us are now. Or ever will be.


Tell me about the scientific evidence of "our creator".
Torbjorn_Larsson_OM
5 / 5 (12) Sep 10, 2012
Creationists shouldn't comment on science, it is hilarious to see.

Those berries are really smart in comparison. At least they evolve as the genome learns from evidence under selection.

Creationists makes shit up, such as gods, in the face of evidence for the contrary. The wouldn't last a generation if fitness of ideas were the measure whereby ideological traits were fixated.
antialias_physorg
4.6 / 5 (11) Sep 11, 2012
Our Creator is very smart. Smarter than any of us are now. Or ever will be.

Well, a non-entity is certainly smarter than you'll ever be. We can all agree on that.
alfie_null
3 / 5 (2) Sep 11, 2012
Yum. Attractive fruit. Should synthesize a topping that has this iridescent effect, use it to get kids to eat their vegetables.
kochevnik
3 / 5 (8) Sep 11, 2012
Our Creator is very smart. Smarter than any of us are now. Or ever will be.
Sorry to hear you are the underachiever of your family. Maybe if you addressed your parents by their names instead of a title you could make progress.
verkle
1.6 / 5 (14) Sep 11, 2012
I really surprised that phys.org has taken the action to take down my comments.

And it has allowed some people above to make nonsense remarks about the Bible and religion that shows they have not even read it.

The scientific evidence for our Creator is all around us. I don't think I have to elaborate any further.

I'm sorry I have been the underachiever of my family. I received only 3 college degrees, perhaps not as many as some of you.

But please, if people are allowed to keep talking about a man-made story of evolution which is not scientific and which has never been put through scientific rigor, allow me to occasionally share my belief of where all of natures wonders came from.

Please allow me at least that respect.

Courteously submitted,

antialias_physorg
4.1 / 5 (9) Sep 11, 2012
I really surprised that phys.org has taken the action to take down my comments

Then you might want to sneak a peek at the commenting guidelines.
http://phys.org/help/comments/
And it has allowed some people above to make nonsense remarks about the Bible and religion that shows they have not even read it.

Wrong. I probably know it better than you do.
The scientific evidence for our Creator is all around us.

Present it. Don't be vague. Point to something TESTABLE.
I don't think I have to elaborate any further.

Yes you do. Because that statement otherwise reads "please, dear god, don't make anyone question me any further for I have no clue what I talk about"

Hic Rhodus. Hic salta.

Please allow me at least that respect.

No. Stupidity and ignorance do not command respect (not even tolerance). Respect is something you have to EARN.
xen_uno
4.3 / 5 (6) Sep 11, 2012
In my case, everything I said PROVES that I've read your bible. Face it, your just another religious troll that believes in fantasy, and can't be bothered with scientific evidence contrary to your beliefs. By the way, degrees in Theology, Political Science, Basket Weaving ... whatever ... does not impress me.
krundoloss
4 / 5 (8) Sep 11, 2012
It is so funny to me when Creationist point to something and say "How could that have evolved, it was obviously created by God". All you are saying is "I don't understand the mechanisms of evolution, so let me just convert my ignorance to faith and say that an all powerful being designed it for fun, because I can understand that." Face it, all religion does is try to explain the unexplainable, and comfort those who cannot handle the fact that there are just some things we don't know, we cannot know, and we couldn't understand even if we did know.
Torbjorn_Larsson_OM
4.3 / 5 (6) Sep 11, 2012
Creationists shouldn't comment on science, it is hilarious to see.

"And it has allowed some people above to make nonsense remarks about the Bible and religion that shows they have not even read it."

See how counterproductive it is to insert religion into society. Religion poisons everything, including science site's threads.

And the comment is a fractal error set. Here it is claimed, despite statistical evidence to the contrary, that creationists knows religious texts or religious issues better than secular people. _This is wrong according to the Pew surveys_, except for a few religious groups like jews that actually know their own texts and issues better.

It has been noted many times that if the religious knew their religious texts or what they are about they too would stop being religious. This is after all what happened with many seculars, they started out religious, then actually read and responded appropriately to the texts and sermons.
Torbjorn_Larsson_OM
4.3 / 5 (6) Sep 11, 2012
The theory of physicalism, no gods, is amply tested by the observed absence of magic. Since about the 70's-80's it is likely a 3 sigma observation (enough tested theories based on energy conservation) that there is no magic energies in action, local energy conservation is absolute.

It is utterly absurd to claim that there is "scientific evidence" to the contrary, or that evolution isn't the accepted basic theory of biology, and so of course no references are given by the 'scientific minded' creationist.

Religion is in the business to replace facts with belief, and science is in the business to replace belief with facts. Every time creationists comment on science this observation is tested, so thanks for adding to the data that religion is bunkum.
verkle
1.4 / 5 (11) Sep 11, 2012
It is truly amazing to see the hypocrisy of God-haters on this forum. You can rank me a "1" and report me for mentioning religion, then you yourselves go on and rant and rave about religion and God, using vulgar language, calling people names, and spewing more utter nonsense.

Then on top of it all, you claim to have a hold on science, and say that anyone who believes in the Bible shouldn't even participate!

Well, you can believe this way if you want to throw out Copernicus, Kepler, Galileo, Descartes, Newton, Boyle, Mendel, Kelvin, Planck.... You can disown them if you want, but you owe them a lot to where you stand today. And they were all believers in the Bible and took theology seriously.

xen_uno
5 / 5 (3) Sep 12, 2012
God haters ... lol! As if there were one to hate. You were given valid reasons for our disbelief's. Science is based on fact and is always evolving as new evidence comes to light. Religion is based on mythology and historical revisionism, whether that base is the bible or the quran. Is there not only one truth? Why then are there so many different religions? What makes yours better than theirs? I'm quite interested in seeing you disprove what science has already proven. The burden of proof is on you, til then your just another flame baiter, which is the reason for your "1".
verkle
1 / 5 (7) Sep 12, 2012
Xen--you ignored my comments. Why should I even bother to address your misguided questions?

Sigh....But I will make 1 comment: I am not interested, neither do I ever want to try, to disprove what science has proven. How could you even make such a statement? Nothing could be further from my heart and mind.

I guess it shows that you really don't understand me at all.

antialias_physorg
5 / 5 (8) Sep 12, 2012
It is truly amazing to see the hypocrisy of God-haters on this forum

No. What IS truly amazing is that people who read the Bible (i.e. who therefore presumably CAN READ) are not able to read the commenting guidelines.

Then on top of it all, you claim to have a hold on science, and say that anyone who believes in the Bible shouldn't even participate!

Yes. Because anyone who has an (unshakeable) belief (in anything - not just gods) is incapable of understanding what science is about. Science is about questioning things. Trying to get at better models which IN TURN are then there to be questioned (and tested) again and again and again...

So you see: A believer is out of his depth in anything science related to the point where their comments mean nothing. It would be like me telling you that I know (better than you) which color your sky fairy's beard is.
antialias_physorg
5 / 5 (6) Sep 12, 2012
neither do I ever want to try, to disprove what science has proven.

This is a perfect case in point that you do not understand science: Science PROVES nothing (science can disprove stuff, but never, with utter finality, prove anything)

I guess it shows that you really don't understand me at all.

Who cares enough to want to understand you? This isn't a psychology self-help group. This is a forum where people come to discuss articles about science. Those who do not wish to discuss science (or who are incapable of doing so - like yourself) should not be surprised that they are not welcomed with open arms.
Sonhouse
not rated yet Sep 15, 2012
I wonder if you eat a lot of Pollia condensata fruit your stool will glow blue.
It happens with carrots.


Carrots makes your stool glow blue?
defactoseven
not rated yet Sep 15, 2012
No, creationists make your stool glow blue.
MNIce
1 / 5 (4) Sep 15, 2012
I am amazed at the irrationality of some of the assertions posted here. For example, one writer claims to have "evidence to the contrary" to the hypothesis that there is at least one god. One must have a god-like knowledge of the universe and whatever is beyond it to know there is no god.

Another claims, "The theory of physicalism, no gods, is amply tested by the observed absence of magic." It does not follow that the existence of a god implies the existence of magic, nor does the existence of magic imply there is a god.

And yet another asserts that his posts prove he has read the Bible, but his unsupportable, ahistorical claims regarding its origins and meaning only prove that it is possible to read something without understanding it. Maybe he doesn't like what Psalm 14:1 says about him, so he closes his mind to the rest. More likely, he takes great pride in his belief that nothing created everything, so he sneers at those who doubt that is possible.
kochevnik
3 / 5 (2) Sep 16, 2012
The scientific evidence for our Creator is all around us. I don't think I have to elaborate any further.
Then you should hire a housekeeper for your filthy parents.
JRDarby
not rated yet Sep 16, 2012
How did an article about something so beautiful and interesting degenerate so quickly into an insult-laden shouting match? Nothing you say will change the other's mind, so just leave it and enjoy the fruits (ha) of Vignolini's work.
rmfouche
not rated yet Sep 17, 2012
I wonder if you eat a lot of Pollia condensata fruit your stool will [turn the same color as the fruit]. It happens with carrots.

Beta carotene (the major component of a carrot's color) is a pigment, which -- if eaten in great quantities -- will discolor stool and even skin. I do not think the same would occur with pollia condensata, as the majority of its color is optical. The cell structure would have to survive ingestion in order to continue to appear iridescent blue.
nate_nordstrom
2.3 / 5 (3) Sep 17, 2012
Ahem, why is there so much hate being thrown around here? Where is the respectful debate?

There is no reliable evidence for MACRO evolution, which is very different than MICRO evolution (adaptation) WITHIN a species.
antialias_physorg
5 / 5 (1) Sep 17, 2012
}There is no reliable evidence for MACRO evolutionq

Are you aware of something called (celular) 'biology'?
Are you aware of something called 'fossil record'?
If so then you know that your statement is pure hogwash.
Silentsam
5 / 5 (1) Sep 20, 2012
Ahem, why is there so much hate being thrown around here? Where is the respectful debate?

There is no reliable evidence for MACRO evolution, which is very different than MICRO evolution (adaptation) WITHIN a species.

What is this MACRO evolution you speak of? Oh, that term made up by creationists who do not understand evolution...

What you call MACRO evolution, is just what you call MICRO evolution time. Those MICRO steps become MACRO steps given the time scales they happen on.

Saying MACRO evolution is as stupid as saying Transitional form. Every living thing is a from between the one that came before, and the one that will come after.
vesper meeps
not rated yet Sep 20, 2012
How did an article about something so beautiful and interesting degenerate so quickly into an insult-laden shouting match?

I'm with JRDarby. It seems to me fundamentalists of every stripe have the same problem; they don't appreciate the social significance of 'the tentatives voice in its authorative mode', which is anything but dogmatic, be they theist or atheist.

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