"This is a really fundamental discovery in the mechanics of plant growth that eventually could have several practical applications," said Nick Carpita, a botany and plant pathology professor. "These could include controlling crop plant size and shape, improving desirable textural properties of fruits and vegetables, and enhancing nutritional fibers in plant cell walls without changing other plant structural factors."
Before these goals can be accomplished, however, the scientists must learn as much as possible about how plant cell walls are created and evolve, he said.
Plant cell walls are composites of minute plant fibers interlaced with many different chains of simple sugars, or polymers, that make the structure strong, Carpita said. While studying how cell walls change as plants develop, his research team discovered that an enzyme requires a simple milk sugar, called galactose, to relace polymers during growth.
The scientists report their findings in the January issue of the journal Plant Physiology.
"A plant cell is essentially concentric rings or spools of cellulose, so when the cells expand, the microfibrils of the wall spread apart," Carpita said. "New microfibrils, or minute organic plant fibers, that are synthesized during growth are continually integrated from the inner rings into the outer rings.
"This process prevents the thickness of the wall from changing even as the cell increases 100 or 1,000 times its length."
The galactose needed to ensure wall strength during plant cell growth is attached to some long polymers, he said. However, abnormal plants, or mutants, that are missing the simple sugars lose cell wall tensile strength.
Xyloglucan, a sugar polymer that has several molecules of simple s
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Contact: Susan A. Steeves
ssteeves@purdue.edu
765-496-7481
Purdue University
20-Jan-2004