Computer scientists in Canada have worked with botanists in Switzerland to build a 3D computer model which simulates how plants grow and develop beautiful shapes. Their model was able to accurately show how plants achieve phyllotaxis, this regular arrangement of lateral organs around a central axis. According to the researchers, this model will be used by botanists to complement and interpret laboratory experiments. But it also could be used as a basis for models of how other organisms, including animals, develop from primordial stem cells.
The computer simulation was designed at the University of Calgary by professor Przemyslaw Prusinkiewicz, and his team at the Graphics Jungle Research Lab, including PhD student Richard Smith, who describes the characteristics of the computer model.
"Biologists have many theories about why phyllotaxis exists but have always wondered how it happens," said Smith. "This model is exciting because it proposes a mechanism that works and can be used to try and prove some of the biological theories about the growth process."
Here is a short description of what the team achieved with this computer model.
Smith and Prusinkiewicz worked with the botanists in Switzerland to create a three-dimensional simulation of plant growth at the microscopic scale, simulating cell division and showing how concentrations of the fundamental plant growth hormone auxin appear at regularly-spaced intervals. This creates the striking spiral patterns of seeds observed in sunflowers, daisies, and many other plants. Other patterns, such as branching at right angles observed in lilac branching, can be also be simulated using different parameter values.
The researchers have used a plant called Arabidopsis for this project, but this is not the first time that they carefully studied this plant. For example, the pictures below some comparisons of sample Arabidopsis plants (A, C, E) with a model integrating a large amount of experimental data (B, D, F). These comparisons have been measured in 'hours from sowing' (hfs): A and B, at 264 hfs; C and D, at 417 hfs; E and F, at 491 hfs. And the scale bar represents 1 centimeter. (Credit: University of Calgary)
This research work has been published online as an open access paper by the Proceedings of the National Academy of Sciences under the name "A plausible model of phyllotaxis" on January 23, 2006. Here are two links to the abstract and the full paper (PDF format, 6 pages, 767 KB).
If you're interested in this subject, you also should read a previous paper published by Plant Physiology in October 2005 under the name "Quantitative Modeling of Arabidopsis Development" (Vol. 139, pp. 960-968). Here are the links to the abstract and to the full paper, from which the above illustration was extracted (PDF format, 9 pages, 263 KB).
The computer scientists think their computer model can be used for animals as well, but is this really feasible? We'll see.
In the mean time, you can use the plant modeling software developed at their Virtual Laboratory and develop your own applications.
Sources: University of Calgary news release, via EurekAlert!, January 23, 2006; and various web sites
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