Ethereal magic of bioluminescent organisms
HAVE you ever seen glowing greenish-blue lights coming from the bushes or jungle when you pass by in the evening? Some of us will have childhood memories of ghoulish tales about these strange glowing lights.
The mysterious glow was probably from bioluminescent organisms – nature’s magical creations which may look normal during the day but will reveal their special light once it is dark.
Bioluminescence
Bioluminescence is a combination of two words – bio from the original Greek bios, which means living, and the Latin word lumen, which means light.
It is a natural occurrence of chemiluminescence or light emission through biochemical reaction. Fireflies, angel fish and bivalves can produce this form of light by mixing luciferin – a pigment, with luciferase – an enzyme.
The luciferin reacts with oxygen to emit light. The luciferase acts as a catalyst to speed up the reaction and can be aided by calcium ions or ATP to enhance the reaction.
The reaction can also be seen in bacteria where it is controlled by an operon called lux operon.
Early records
In 382 BC, Aristotle wrote the oldest record of foxfire. He noted the light was not like fire because it was cold to touch but was unable to explain why.
Early naturalists and scientists could only guess the cause as the study of biochemistry had not been developed then. The true cause was discovered in 1823, when wooden beams used to support mines were examined closely and found to have fungi, which gave out light, growing on them.
The famous Mark Twain book ‘The Adventures of Huckleberry Finn’ featured foxfire being used by Huck and Tom Sawyer.
Glowing fungi
A total of 71 species of fungi are known to be bioluminescent including in the following families – Omphalotus, Mycena, Gerronema, Armillaria, and Pleurotus.
Foxfire
This is also known as fairy fire in traditional storybooks. It is actually created by the presence of the Armillaria fungi in decaying wood. The bluish-green light is attributed to the luciferase reacting with luciferin.
The actual purpose of the coloured light is not known, but it is believed to attract insects to spread spores to wider areas of coverage or act as a warning to animals not to eat them – for poisonous and unpalatable species. Some areas with a heavy presence of fungi can emit enough light to read by.
The Armillaria mellea is the most widely found in almost all areas including Borneo. This fungus has a luminous greenish light with a wavelength from 520 to 530 ranges.
Some of the fungi have luminous spores, mushrooms and even rhizomorphs. In Malaysia we have the Armillaria fuscipes with luminous mycelia but not the body itself. Another species called Filoboletus pallescens has a luminous body. The Mycena chlorophos is bioluminescent all over.
An interesting point about this saprophyte fungus is that it is the largest single living organism in the world. A single organism of the species Armillaria solidipes can cover an area of 3.4 square miles and is thousands of years old.
As a forest pathogen, it is destructive on one hand but a great waste disposer too. Rubber and cocoa white root disease are two very common examples in our rural living encounters.
This fungus can invade the living tissues of the trees by gradually attacking the roots, thereby extracting nutrients from the host plants. The Ukrainian and Canadian honey fungus actually refers to a fungus beneath the stump.
The fruit bodies of the fungus are known as mushrooms that grow on wood as dense clumps or tufts. The caps of these mushrooms are an umbrella shape with slight variations such as conical to convex and yellowish or white in colour. They are somewhat sticky to touch and the gills on the ventral side produce spores.
Glowing moss
Another group of plants that have the ability to glow are the moss also known as Elfingold (Schistostega pennata) growing mainly in the northern hemisphere.
It forms green mats in caves, holes in wood or earth, or cavities between rocks and under tree roots. It is the tiny spore capsules that can reflect light from chlorophyll grains in lens-shaped cells of the protonema. Protonema is the filamentous structure growing from the germinating spore that eventually becomes a new gametophyte or tiny plant just about half an inch tall. All these are parts of the lower classes of the plant kingdom.
Glow in the dark
Other than bioluminescent plants, fireflies or Lampyridae found all over the world also add a glow to evening skies. Fireflies glow due to the mixing of chemicals in their bodies. According to research from Japan, the phosphorus compounds when mixed can produce a cool light. Fireflies are known to synchronise the rhythm of lights as a mating signal.
Many fish and marine creatures also use light in the depths of the sea. Glowworms found in the Mulu Caves do too. There are various groups of insect larvae, adult larviform females and beetles that are bioluminescent.
All of these are part of the wonders of nature. Happy gardening.