Have you ever heard of the Monotropa uniflora? It’s also known as the ghost plant.
Why Are Plants Colored in the First Place?
The vast majority of plants (I’m even including algae here) photosynthesize. This means they take energy from the sun to grow. Without going into too much detail, they can capture a particular wavelength of sunlight. To our eyes, this looks white, but it actually contains the whole spectrum of colors. If plants are green, it’s because they can use all wavelengths of light… except green light. As they don’t “absorb” green light, it is reflected, which explains why, to our eyes, plants are predominantly green.
Some are purple or red (many algae living below the surface are actually red!). Quite simply, they absorb different wavelengths (colors).
For example, the deeper you go beneath the water’s surface, the less red light you see. At a depth of around ten meters, there’s no red in the light at all (which is why water looks blue to us!). Logically, algae living at this depth have no need to synthesize red light. As they cannot “absorb” this wavelength, it is reflected, which explains why, to our eyes, once out of the water, these algae are… red!
Logically, then, if a leaf is white, it can’t absorb any of the different colors of light. In fact, white represents all the colors of the light spectrum, so a white leaf that reflects all the colors… doesn’t photosynthesize. Fans of white marbled plants can testify to this: if a leaf emerges and is entirely white, it doesn’t survive.
No Color, No Photosynthesis… What About the Ghost Plant?
For this reason, it’s very rare to see completely white plants, especially in the wild. In fact, the uniflorous monotrope is the only plant I know that has this lifestyle. And it’s so unusual that it’s often mistaken for a mushroom!
I can assure you that the ghost plant is a real plant, and also that it’s completely white. There’s no hidden green tip. So how does it live and generate energy without photosynthesis?
The answer is simple: it evolved by taking its energy from somewhere other than sunlight.
This parasitic plant has a mycorrhizal symbiotic relationship.
Symbioses vs. Parasites
A little vocabulary:
There are many types of interaction in nature. Some are beneficial to both parties. Such is the case with mycorrhizal fungi: they connect underground with tree roots, supplying them with water and minerals drawn from the soil. In return, the tree gives the fungus a share of the energy, in the form of carbohydrates (sugars), that it has produced through photosynthesis. It’s a win-win situation! This type of relationship is known as mutualistic symbiosis, and it’s a win-win situation.
In simple terms, it’s like buying produce from a producer: we give him money to continue producing, and he gives us food to… well… live on. Strictly speaking, we don’t depend on the producer, but we do each other a favor by exchanging our resources.
We can also compare our relationship with a dog: we give him food, and he gives us love!
A parasitic relationship, on the other hand, is when only one party benefits. Lice, mosquitoes and bedbugs feed on you, and it’s not pleasant. It doesn’t benefit you, it harms you.
Japanese beetles feed on plants and damage their leaves, sometimes even killing them.
Cats take advantage of you, your money, your time, your sleep, and… give you nothing in return! (No bias here, it’s a completely objective comment! Hihi!)
Conclusion: mycorrhizal fungi and trees are perfectly happy together, until Mr. Monotrope comes along and parasitizes this relationship, providing himself with the water, minerals and carbohydrates he needs: a symbiotic parasite!
(I hope everyone’s following along, there really are a lot of possible relationship types in nature and they all have a little name, but we’ll stick to these two for today.)
So this ghost plant could live in total darkness, as long as it has its underground suppliers. I don’t know about you, but it reminds me more of a zombie than a ghost.
Otherwise, Everything Is Normal With This Plant!
Apart from this rather unique way of feeding, its immaculate color and lack of leaves, it’s a fairly common plant. It is pollinated by bumblebees and flies, and once fertilized, the flower produces a fruit. The seeds are very small, less than a millimeter, and are sometimes eaten by certain herbivores such as butterfly larvae.
The presence of ghost plants is quite random: not only do they have to find a mycorrhizal symbiosis to parasitize, but meteorological conditions also mean that their emergence varies from year to year. An individual plant may produce several flowers, or just one, or remain dormant all summer.
And so it goes! One more of nature’s mysteries uncovered by your favorite biologist! (Me, a big head? Your fault! With all your lovely comments every week!)