Plant biologists from Stanford University and the Carnegie Institution of Washington report their new findings in the April 24 online edition of Science Express. The researchers are the first to witness the birth and growth of individual "microtubules" nanosize tubes of protein that form inside living plant cells.

"We have a strong interest in cell growth, form and development, and microtubules play a prominent role in all three," said Stanford scientist Sidney L. Shaw, lead author of the Science study. Shaw is a research associate in the laboratory of Sharon Long, a professor of biological sciences and dean of Stanford's School of Humanities and Sciences.

"Imagine the plant cell as a cylinder with many thin rods, or microtubules, laying along parallel lines just under the surface," noted co-author David W. Ehrhardt, a staff scientist in the Carnegie Institution's Department of Plant Biology located on the Stanford campus. The microtubules form specific patterns that determine the eventual shape of the cell and ultimately the shape of the plant, he explained.

"If plant cells didn't have a particular shape, we wouldn't see trees and grass grow as they do. They'd be squat and lumpy, lacking much of the diversity of form that plays important roles in physiological and ecological function and also makes plants fun to garden with," Ehrhardt added.

Tracks and girders

A microtubule is only about 25 nanometers in diameter roughly 2,000 times narrower than a human hair. Found in all plant and animal cells, these hollow rods of protein assemble spontaneously and carry out a number of important functions. Some act as miniature girders that support the cell
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Contact: Mark Shwartz
mshwartz@stanford.edu
831-239-3312
Stanford University
24-Apr-2003