The extraterrestrial botanist
By Sanjida O'Connell
Excerpt: newscientist.com
January 3, 2009 - Jodie Holt, a professor of plant physiology at the University of California, Riverside, served as the botanical advisor to the film Avatar, which opens in theatres this week. She talks with me about the unique combination of science and imagination that it takes to create alien plant life.
What was your involvement with Avatar?
The plants in Avatar had already been created when I got involved, so initially my role was to advise Sigourney Weaver, who plays a botanist in the film. Later James Cameron's company, Lightstorm Entertainment, asked me to write a description of every plant for games they've developed.
So I got to make up descriptions, characteristics and Latin names. Some are carnivorous, fluorescent, shoot poisonous leaf tips; others are able to move or are magnetic.
Where did you begin when thinking about what plant life might be like on the planet of Pandora?
The first thing that popped into my head was, what are the biological principles here, how did these plants evolve and become adapted to the conditions on the planet? What really stumped me in the beginning was that Pandora looks like a rainforest: it's very lush, yet there are plants that look like succulents, which grow in deserts.
Clearly this was because someone who wasn't a botanist had created these plants. But if I'd designed them, they would have looked too normal. So I decided that these succulents could have evolved if water was locked up in toxic soil and was unavailable to them.
Although I didn't create the plants I might have influenced the colour. When I first saw the plants they were blue and I blanched. You don't get the warm and fuzzies about a blue plant.
What advice did you give to Sigourney Weaver?
Sigourney plays a botanist in a new location who walks around and discovers plants, learns about them and tells people what they are. I met with her and the set designer and they wanted to know what I wear and carry with me on my field trips and what observations, measurements and samples I would take.
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Inventing the plants of Avatar
A plant physiologist from UC Riverside helped create the exotic flora seen in the movie. 'What botanist would not want to "discover" new plants and name them?' she says.
By Lori Kozlowski | Source: latimes.com
January 3, 2009 - James Cameron's science-fiction blockbuster "Avatar" takes place in 2154 on the lush moon Pandora. To help make the set believable, Jodie Holt, chairwoman of the department of botany and plant sciences at UC Riverside, was approached to consult on the film's plant life, as well as how a botanist would study such flora.
Holt, a plant physiologist, talked about her involvement in the film and the "Pandorapedia," a detailed catalog of the moon's features, including its many plants.
How did you become involved in the film?
I was called by Nicole Pitesa, [producer] Jon Landau's assistant, in early 2007; she asked if I would be interested in advising an A-list actress in "Avatar" on how to be a credible botanist. The movie was in preproduction at that time. I later learned that Nicole had searched local universities for botany departments and found us at UC Riverside.
What type of advice did you lend them?
After being briefed on the plot and being shown early images of the plants on Pandora by Jon Landau, I met with Sigourney Weaver [who plays botanist Grace Augustine] and set designers to talk about how a field botanist would study and sample plants to learn about their physiology and biochemistry. We also talked about the idea of communication among plants, and between plants and the Na'vi, and how that might be explained. Subsequently, I worked with a set designer to ensure that his designs for the field and lab equipment were credible.
Can you give specific examples about the set?
I did not work on all the scientific sets and props by any means. What we talked about was the concept of plant communication, which is integral to the movie, and how this could be studied by Grace.
Since life on Pandora was intended to adhere to our known laws of physics and biology, it was not credible to me to suggest that the plants had any kind of nervous system. Instead, I suggested that communication among the plants could credibly be explained by signal transduction, an area of research that deals with how plants perceive a signal and respond to it. Since this process is still not well understood but is under active investigation, it made sense to use it as an explanation for Grace's more futuristic understanding of plants. Subsequently, the set designer and I exchanged many e-mails about how Grace might sample plants and study this process.
In the actual movie, which I've now seen four times, I studied the equipment and labs -- and everything looks just fine and quite credible. The only real sample one sees Grace take is with a syringe, which is a reasonable thing to do. As far as field equipment goes, we agreed that 150 years in the future the equipment would likely be much smaller and more efficient, hence the small packs the scientists carried.
Overall I thought the science in the movie was fantastic! However, several of my colleagues noted, as I did, that the fact that Grace smoked could be a problem in the lab. The tobacco mosaic virus is common on cigarette tobacco and can easily be transmitted from a smoker's hands to biological samples and contaminate them. I was never consulted about the smoking, as this was a part of Grace's character separate from the science. Only biologists in the audience who work with molecular samples would think of this, however.
Later, in the fall of 2008, Jon Landau called to ask if I would be interested in writing descriptions of the plants, including fabricating Latin names, to be included in the games and book that were planned. The result was a set of Pandorapedia entries, completed in early 2009.
What were some of the names in the Pandorapedia?
In mid-December, a book was published called "Avatar: An Activist Survival Guide." The plant descriptions I wrote are in Chapter 4. These include taxonomy (Latin names I made up using the correct rules of nomenclature), a description of each plant, and information about ecology and ethnobotany. Since some of the plants looked like Earth plants, while others were quite fantastic, and others resembled each other, I started by grouping them by somewhat similar appearance to develop a crude taxonomy.
For plants that resembled Earth plants, I gave them similar names, such as Pseudocycas altissima for a plant that looks like a tall Earth cycad. Others I named for their appearance, such as Obesus rotundus for the puffball tree.
This project was very challenging but also a lot of fun. What botanist would not want to "discover" new plants and name them herself?
I understand that some of these Pandorapedia entries are also contained in the games that were released. However, my husband and I have not yet achieved much proficiency at the video game, so we have not been able to explore Pandora and learn about the plants that way. Hopefully, we can get my young nephew to help us.
Did the film challenge you to think about what plants will look like in the future?
No, the movie is only about 150 years into the future, which is not a lot of time for major evolutionary advances. The real question I dealt with in working on both the movie and the Pandorapedia was how the environment on Pandora would have selected the many unusual, bizarre plants found there, as well as some that look very much like plants currently found on Earth.
I wrote an essay on this, which is also in the "Avatar Survival Guide." The information on the environment of Pandora -- including the atmosphere, soil, gravity, etc. -- was provided by James Cameron, and I had to piece it together to create a credible explanation for how this environment would have selected the many strange plants on Pandora with their unusual adaptations.
For example, the atmosphere is thicker than on Earth, with higher concentrations of carbon dioxide, as well as xenon and hydrogen sulfide. Gravity is weaker. And there is a strong magnetic field. Given the role of the environment in plant evolution, one would therefore expect to see gigantism, less of a gravity response (which makes stems grow up and roots grow down), and possibly a response to magnetic fields, which I named "magnetotropism."
Are there specific plants that you are most familiar with? Did this background aid the film in some way?
At UC Riverside, I study weedy and invasive plants. However, all my degrees are in botany and I have taught general botany for 12 years. In this class, I routinely challenge students to analyze plant morphology and anatomy to explain plant adaptations to the environment. These experiences teaching botany were incredibly useful to me in working on the movie.
Thanks to AMZ Forum Member Suzy for contributing this link.
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The Shocking Colors of Alien Plants
Source: Scientific American Magazine
Article By Nancy Y. Kiang | April 2008 Issue
The prospect of finding extraterrestrial life is no longer the domain of science fiction or UFO hunters. Rather than waiting for aliens to come to us, we are looking for them. We may not find technologically advanced civilizations, but we can look for the physical and chemical signs of fundamental life processes: “biosignatures.”
Beyond the solar system, astronomers have discovered more than 200 worlds orbiting other stars, socalled extrasolar planets. Although we have not been able to tell whether these planets harbor life, it is only a matter of time now.
Last July astronomers confirmed the presence of water vapor on an extrasolar planet by observing the passage of starlight through the planet’s atmosphere. The world’s space agencies are now developing telescopes that will search for signs of life on Earth-size planets by observing the planets’ light spectra.
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Photosynthesis, in particular, could produce very conspicuous biosignatures. How plausible is it for photosynthesis to arise on another planet? Very. On Earth, the process is so successful that it is the foundation for nearly all life. Although some organisms live off the heat and methane of oceanic hydrothermal vents, the rich ecosystems on the planet’s surface all depend on sunlight.
Photosynthetic biosignatures could be of two kinds: biologically generated atmospheric gases such as oxygen and its product, ozone; and surface colors that indicate the presence of specialized pigments such as green chlorophyll. The idea of looking for such pigments has a long history. A century ago astronomers sought to attribute the seasonal darkening of Mars to the growth of vegetation. They studied the spectrum of light reflected off the surface for signs of green plants.
One difficulty with this strategy was evident to writer H. G. Wells, who imagined a different scenario in The War of the Worlds: “The vegetable kingdom in Mars, instead of having green for a dominant colour, is of a vivid blood-red tint.” Although we now know that Mars has no surface vegetation (the darkening is caused by dust storms), Wells was prescient in speculating that photosynthetic organisms on another planet might not be green.
Even Earth has a diversity of photosynthetic organisms besides green plants. Some land plants have red leaves, and underwater algae and photosynthetic bacteria come in a rainbow of colors. Purple bacteria soak up solar infrared radiation as well as visible light. So what will dominate on another planet? And how will we know when we see it?
The answers depend on the details of how alien photosynthesis adapts to light from a parent star of a different type than our sun, filtered through an atmosphere that may not have the same composition as Earth’s.
Harvesting Light
In trying to figure out how photosynthesis might operate on other planets, the first step is to explain it on Earth. The energy spectrum of sunlight at Earth’s surface peaks in the blue-green, so scientists have long scratched their heads about why plants reflect green, thereby wasting what appears to be the best available light. The answer is that photosynthesis does not depend on the total amount of light energy but on the energy per photon and the number of photons that make up the light.
Whereas blue photons carry more energy than red ones, the sun emits more of the red kind. Plants use blue photons for their quality and red photons for their quantity. The green photons that lie in between have neither the energy nor the numbers, so plants have adapted to absorb fewer of them.
The basic photosynthetic process, which fixes one carbon atom (obtained from carbon dioxide, CO2) into a simple sugar molecule, requires a minimum of eight photons. It takes one photon to split an oxygen-hydrogen bond in water (H2O) and thereby to obtain an electron for biochemical reactions. A total of four such bonds must be broken to create an oxygen molecule (O2). Each of those photons is matched by at least one additional photon for a second type of reaction to form the sugar. Each photon must have a minimum amount of energy to drive the reactions.
The way plants harvest sunlight is a marvel of nature. Photosynthetic pigments such as chlorophyll are not isolated molecules. They operate in a network like an array of antennas, each tuned to pick out photons of particular wavelengths. Chlorophyll preferentially absorbs red and blue light, and carotenoid pigments (which produce the vibrant reds and yellows of fall foliage) pick up a slightly different shade of blue.
All this energy gets funneled to a special chlorophyll molecule at a chemical reaction center, which splits water and releases oxygen.
The funneling process is the key to which colors the pigments select. The complex of molecules at the reaction center can perform chemical reactions only if it receives a red photon or the equivalent amount of energy in some other form. To take advantage of blue photons, the antenna pigments work in concert to convert the high energy (from blue photons) to a lower energy (redder), like a series of step-down transformers that reduces the 100,000 volts of electric power lines to the 120 or 240 volts of a wall outlet.
The process begins when a blue photon hits a blue-absorbing pigment and energizes one of the electrons in the molecule. When that electron drops back down to its original state, it releases this energy—but because of energy losses to heat and vibrations, it releases less energy than it absorbed.
The pigment molecule releases its energy not in the form of another photon but in the form of an electrical interaction with another pigment molecule that is able to absorb energy at that lower level. This pigment, in turn, releases an even lower amount of energy, and so the process continues until the original blue photon energy has been downgraded to red.
For the full article and more astounding imagery, you can purchase the April 2008 issue of Scientific American online.
Click here for details.
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