Like Origami, Pollen Grains Fold Just So
By Henry Fountain, The New York Times
April 26, 2010
After it is released from a flower’s anther, a pollen grain walks a humidity tightrope. It
dries up a bit as it travels through the air, the cellular material inside becoming dormant
so it survives until it reaches the humid environment of another flower’s stigma. But it
can’t become so dry that the material dies.
Eleni Katifori
A scanning electron micrograph of a dehydrated Lily pollen grain.
Pollen grains achieve the proper state of desiccation by folding in on themselves as they
dry, which reduces the rate of water loss (and also accommodates the reduced volume
of water, making the grain smaller). It’s an elegant trick, and the structure of the pollen
grain wall determines how it occurs, according to research published in The Proceedings
of the National Academy of Sciences.
Eleni Katifori, previously at Harvard and at Rockefeller University, and colleagues
studied the folding of pollen from lilies and other flowers (a video of folding grains is at
nytimes.com/science). The walls of pollen grains have weaker, more flexible sections
called apertures, and Dr. Katifori said those sections guide the folding process. Like
origami, in which paper stretches only at the creases, pollen grains deform at the
apertures “so the rest can fold without stretching,” she said.
“It’s like pulling the air out of a beach ball,” she said. “Parts of the wall have to comply to
accommodate the change of volume.”
Dr. Katifori said the goal of the research was to discover the basic principles by which
the folding occurs as a way of understanding some of the functional demands that drive
the great diversity of pollen grain structures in nature. But she said that the work might
also prove useful to those who design structures. “I could imagine that engineers could
get inspiration from just looking at pollen grains,” she said.