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

This odd fruit have really extraordinary iridescent colours that are not the result of pigmentation.
Indeed, Pollia condensata fruit, does not get its blue colour from pigment but instead uses structural colour – a method of reflecting light of particular wavelengths.



In the forests of central Africa, there’s a plant that looks like it’s growing its own Christmas decorations. Shiny baubles sprout from between its leaves, shimmering in a vibrant metallic blue. Look closer, and other colours emerge – pinpricks of red, orange, green and violet. It looks as if Seurat, or some other pointillist painter, had turned their hand to sculpture.

But these spheres, of course, are no man-made creations. They’re fruit. They are the shiniest fruits in the world. Actually, they are the shiniest living materials in the world, full-stop.

Most colours around us are the result of pigments. However, a few examples in nature – including the peacock, 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 cellulose. 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.

The color is caused by Bragg reflection of helicoidally stacked cellulose microfibrils that form multilayers in the cell walls of the epicarp. The bright blue coloration of this fruit is more intense than that of any previously described biological material.

Uniquely in nature, the reflected color differs from cell to cell, as the layer thicknesses in the multilayer stack vary, giving the fruit a striking pixelated or pointillist appearance. Because the multilayers form with both helicoidicities, optical characterization reveals that the reflected light from every epidermal cell is polarized circularly either to the left or to the right, a feature that has never previously been observed in a single tissue.

Sources:
- Phys.org
- Pnas.org
- Nature.com
- Discovermagazine.com

Nice find.

The closeup of the fruit looks like some blue metal flake Naugahyde that was popular in the 1970's.

This is amazing.

I would love to know how this will effect views on items we know about already.

How can we use this for our own advantages as well?

Evolutionary theory states that specific traits within an organism or species "evolved" through a process of natural selection. This is a hypothetical process whereby randomly occurring mutations are "locked" in if they provide some kind of advantage to the species.

However, having read the article explaining the physics behind this particular plants ability to refract light of a specific frequency, I have to admit to being somewhat stumped as to how and why all the necessary individual sub-components evolved separately and yet were ALL available exactly when the plant required the ability to refract light with a blue frequency component.
After all, this refraction "trick" is a highly complex process and reliant on every sub-component having already evolved at some earlier time, and successfully stored and retained, within the plants genetic structure. So if the sub-components individually (presumably) provide little or no significant survival value to this species, then one has to ask the following questions:
(1) why did the sub-components evolve in the 1st place ?
(2) once evolved, why were they retained within the genetic framework ?

You raise a very good point, How does an item evolve in separate stages but all at the same time.

Have you seen any thing else like this?

looks pretty cool! can you eat it???

Originally posted by AnonUK
You raise a very good point, How does an item evolve in separate stages but all at the same time.

Have you seen any thing else like this?

Two other examples immediately come to mind ... both in us humans:
(1) The ear is a complex mechanical structure relying on numerous individual sub-components working together perfectly to enable pressure waves from the outside being guided to a inner flexible membrane ... that together with other mechanical components, eventually converts the pressure wave into an electrical signal.
(2) The eye is another highly complex structure incorporating moving/flexing sub-components that are capable of manipulating and processing light according to optical laws ... eventually converting a photonic impulse into an electrical signal.

Both the above examples depend on their very function (and existence) on previously evolved sub-components.
Again, the question can be asked as to what process caused these individual sub-components to evolve and be genetically stored until every required piece was available to produce the finished product.

reply to post by elevenaugust


The same goes for birds like crows.
To us they look black and all the same.
To the crows they look each different.
It is done in the same way, without pigments in the feathers, and crows can see a bit more in the UV range

Wow! Lovely what lenghts nature goes to, just to take our breath away.

Of course, my first thought was "wonder what those taste like?"
Bet it'd make some neat looking sherbert.

reply to post by elevenaugust

Indeed, Pollia condensata fruit, does not get its blue colour from pigment but instead uses structural colour – a method of reflecting light of particular wavelengths.

Even with pigment, colors are always particular reflected wavelengths of light.

A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption.

en.wikipedia.org...

Very cool.

I would be the first to eat those berries i am afraid to say, they look delicious.

Nature can be and is the inspiration for much of what we have to.

We continue to learn new things as we try to emulate parts of nature that can best serve us.

Good find

What beautiful beautiful berries. I didn't know nature made metalic finish fruit! It puts some fancy car paint jobs to shame.
Very nice find OP, truly enlightening. S&F.

Great thread. I love anything like this - nature keeps on providing us with nice surprises.

Thanks OP

Originally posted by reficul
looks pretty cool! can you eat it???

That's a good question and here's the answer from discovermagazine.com:

Why does Pollia have such bright fruit? Here’s a clue: you can’t eat them. Well, you can eat them, but there would be no point, because they provide next to no nourishment. They’re practically a dry seed-filled husk. Here’s another clue: Pollia grows in the same regions as another plant, Psychotria peduncularis, which also produces blue berries.

The team thinks that Pollia is mimicking the tasty blue fruits of its neighbour, tempting birds with the promise of tasty pulp, but rewarding them with nothing but seeds to carry. Alternatively, birds could collect the fruits to decorate their nests, or to use in mating displays. Either way, Pollia gets a free ride, and avoids having to spend energy on making sweet, nourishing tissues. It’s an evolutionary triumph of style over substance.

Although using animals for dispersal is a strategy common to many plants, most are forced to devote precious calories to produce a sweet, fleshy pulp. This one, however, is able to spread its seeds simply by showing its true iridescent colors.

reply to post by elevenaugust


ha! sounds like my ex wife!!!!
nice to look at,but no substance!!!

reply to post by elevenaugust


This is the kind of nature we're destroying in favor of a steel jungle, forgetting that true beauty isn't forced.

Thank you for sharing this.

They look like my dad's bowling ball from the early 80's. Nice post!

Maybe I can get a custom van painted like that.

Theres all kinds of car paints like that.....be prepared to spend 200 or more a gallon. Probably needs 3 gallons for your van.

The argument about evolution is funny. Wouldnt the evolution of being yummy be simpler? And what about some disgusting vegetables. Wtf makes people eat asparagus?

When will monsanto make a genetically modifird christmas tree that decorates itself?

Originally posted by elevenaugust

Why does Pollia have such bright fruit? Here’s a clue: you can’t eat them. Well, you can eat them, but there would be no point, because they provide next to no nourishment. They’re practically a dry seed-filled husk. Here’s another clue: Pollia grows in the same regions as another plant, Psychotria peduncularis, which also produces blue berries.

The team thinks that Pollia is mimicking the tasty blue fruits of its neighbour, tempting birds with the promise of tasty pulp, but rewarding them with nothing but seeds to carry. Alternatively, birds could collect the fruits to decorate their nests, or to use in mating displays. Either way, Pollia gets a free ride, and avoids having to spend energy on making sweet, nourishing tissues. It’s an evolutionary triumph of style over substance.

Although using animals for dispersal is a strategy common to many plants, most are forced to devote precious calories to produce a sweet, fleshy pulp. This one, however, is able to spread its seeds simply by showing its true iridescent colors.

That is very interesting...pure colours usually have a specific and enhancing nutritional value, that in itself, is related to colour perception in the species that eat it. This, on the other hand, relies on the bird's eye for 'shiny', purely decorative in it's purpose. How incredibly fascinating!

nvm