Plant science in...

Plant science in Avatar

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In 2009, during the golden-age of 3D cinema, James Cameron’s Avatar hit the screens. The ground-breaking visual effects of Cameron’s $237 million masterpiece transported viewers to a moon orbiting a fictional planet in the Alpha Centauri star system, Pandora. We’re introduced to a densely forested environment, inhabited by ten foot tall, humanoids called Na’vi, specifically the Omaticaya clan, who live harmoniously with nature. For two hours, Cameron transports you to Pandora and fills your vision with captivating flora and fauna. The movie leaves you wishing you were a Na’vi, running through the forest, connecting with the stunning world around you. But you might not have to travel from one star system to another to experience the joys of Pandora. In this blog post, I hope to show you how the magic of Pandora can be found on our own wonderful, little planet.

Home Tree

Hometree (Kelutral, in Na’vi), is home to the Omaticaya clan. At roughly 150m tall and 10,000 years of age, Hometree is a landmark on the Pandoran landscape. With mangrove like roots, it’s suggested that Hometree is actually a collection of trees that have grown together for mutual support and strength. On Earth, this tree immediately reminds me of the Giant Sequoias (Sequoiadendron giganteum) of West Coast America. Giant Sequoias only grow to about a third of the height of Hometree, but these magnificent trees still stand head and shoulders above the rest of the forest canopy. Giant Sequoias are among the oldest living organisms, with the oldest known Sequoia having lived more than 3500 years.

Where Hometree on Pandora really mirrors the story of Giant Sequoias in America is in the destruction and consequential conservation of the two. In the movie Avatar, Hometree is considered an individual that can be destroyed to get to the valuable unobtanium beneath it. However, it is also a part of a complex ecosystem and its value to the Omaticaya is beyond material riches. Giant Sequoias have also historically been looked at as individuals, and managed as such. In more recent years, they have been looked at as part of more complex ecosystems, because the part they play within their habitat is invaluable [1].

In 1853, a Giant Sequoia was brought to the ground after it took a team of men three weeks to cut through its base. The tree was named The Mother of the Forest. Five months later, newspaper reporter Maturin M Ballou remarked:

Although the destruction of such a magnificent object was an act of vandalism not to be forgiven, yet the desecration has been committed, and it is useless now to reiterate our vain regrets”.

But it was not useless. As with many conservation plans, it took several years to pass a bill but in 1872, the “Yosemite Grant” was created and with it, the first official national park was born [2]. In 2000, President Bill Clinton created The Giant Sequoia National Monument, which now protects 38 of the 39 Sequoia groves.

Bioluminescent plants

As night sets in and the sun goes down, the forests of Pandora begin to glow with iridescent hues of blue and purple. After a mysterious encounter with some floating, glowing, dandelion-like seeds, Neytiri and Jake run through the Pandoran undergrowth; the ground lighting up with their every step. I would love to tell you that bioluminescence in plants was natural on Earth. That in the deep Amazonian rain forest, you could run among the trees and trace your steps with gentle glowing cluster of daisies. Unfortunately, this just isn’t true. However, bioluminescence does naturally occur in fungi and researchers have been able to use their DNA to create glowing tobacco plants.

Previous studies have failed to create plants that can glow for the entirety of their life-cycle, brightly and with no obvious side-effects. Last month, however, Mitiouchkina et al. [3] published a paper detailing their genetically engineered, autoluminescent (auto- meaning “without input”) plants, who’s glow is not only bright and visible to the naked eye, but also sustained for the entirety of the plant’s lifecycle. While it’s not a forest, it’s definitely a good start. Imagine a plant nightlight!

I do just want to take a moment to give an honourable mention to the plants that glow under UV light. Unfortunately it isn’t visible to our eyes, but photographer Craig Burrows has captured this phenomenon using Ultraviolet-Induced Visible Fluorescence photography and it is a sight to behold [4].

Plant Communication

Tree of souls

My favourite aspect of the entire Avatar world is The Tree of Souls (Vitraya Ramunong in Na’vi). This giant, fibre-optic willow tree is of great cultural and spiritual importance to the Na’vi, who can connect with their deity Eywa, and the memories of their ancestors through it. Even more incredibly, it appears that The Tree of Souls can communicate with others around it:

What we think we know, is that there’s some kind of electrochemical communication between the roots of the trees.  Like the synapses between neurons. Each tree has ten to the fourth connections to the trees around it, and there are ten to the twelfth trees on Pandora“. – Dr Grace Augustine.

This trait isn’t limited to the trees on Pandora. It has been discovered that this same communication process is possible between trees right here, on Earth. Ecologist Suzanne Simard discovered how trees communicate using an underground, mycorrhizal network. In their roots, trees can host fungi. This is a mutually beneficial relationship (called a mycorrhiza), as the fungi fix vital nutrients in the roots that trees could otherwise not absorb and, in return, trees provide sugars for the fungi.

What do trees have to talk about? A lot, it turns out: warning signals about stress and pests, environmental changes, seeking out their kin and transferring surplus nutrients. What this demonstrates is the importance of relationships within forests. Simard refers to a “mother tree”, which is generally the largest, and acts a central hub in a mycorrhizal network [5]. This is something to consider in logging, forest management and conservation planning. By removing the mother tree, this puts the entire mycchorizal network at risk. I cannot do this subject justice in one blogpost, so I would highly recommend watching Simard’s TED Talk, “How trees talk to each other”:

While escaping into the movie magic of Hollywood is a wonderful way to destress and unwind after the hustle-and-bustle of daily life, I hope you can take comfort in the knowledge that this magic isn’t limited to fictional worlds. There are wonderful, beautiful, magical aspects to the nature all around us – you just have to know where to look.

References

[1] Parsons, D.J. and Aune, P.S., 1994. Objects or ecosystems? Giant sequoia management in national parks. In PS Aune [technical coordinator], Proceedings of the symposium on the Giant Sequioas: Their place in the ecosystem and society (pp. 109-115).

[2] How a giant tree’s death sparked the conservation movement 160 years ago.

[3] Mitiouchkina, T., Mishin, A.S., Somermeyer, L.G., Markina, N.M., Chepurnyh, T.V., Guglya, E.B., Karataeva, T.A., Palkina, K.A., Shakhova, E.S., Fakhranurova, L.I. and Chekova, S.V., 2020. Plants with genetically encoded autoluminescenceNature Biotechnology, pp.1-3.

[4] Pictures capture the invisible glow of flowers.

[5] Simard, S.W., 2009. The foundational role of mycorrhizal networks in self-organization of interior Douglas-fir forestsForest Ecology and Management258, pp.S95-S107.

Image credits

All Avatar images are screenshot from the 2009 film. Rights belong to Disney, I think.

Giant Sequoia: Tuxyso / CC BY-SA.

Glowing tobacco: Science alert.

2 thoughts on “Plant science in Avatar”

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