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For the longest time, scientists believed newly forming leaves on a plant secreted a chemical that inhibited growth of other leaves around it. This process was thought to be the basis for intricate spiral seed patters in sunflowers or the determining factor in the architectural relationship of one branch to another. But other, newer theories raised doubts about the leaf secretion idea.

Now, scientists at the University of Calgary have developed a computer model that lends credence to the new theories. The 3-D model follows the growth of the absolute tip of a growing plant. It took more than two years to develop.

Calgary PhD student Richard Smith says the simulation shows it's possible that carefully timed injections of plant hormones actually trigger new growth.