The Nando Times
WASHINGTON - Don't throw away the lawnmower yet, but scientists have found out a way to stunt the growth of grass and other plants and keep them greener longer by tinkering with a single gene. It could be a dream come true for suburbanites weary of the weekly mowing ritual.
The gene regulates production of a steroid hormone that causes plants to grow, much the same way similar steroids work in animals. Scientists have now succeeded in manipulating the gene to create dwarf versions of standard plant species, according to research published Tuesday in the journal Proceedings of the National Academy of Sciences.
A tobacco plant that would normally grow 6 feet tall was engineered to mature at 12 inches by scientists at the Salk Institute for Biological Studies in San Diego. The same technique worked with the Arabidopsis plant, a member of the mustard family that, like tobacco, is frequently used in genetic studies.
"It very much parallels the steroids in football players. Plants buff up on it," Joanne Chory, the Salk study's senior researcher, said of the newly manipulated plant gene. "If you do something ... so it isn't expressed, you get these little dwarfy guys."
The dwarf versions are identical to the standard plants in every way but size, she said.
Plant breeders have long searched for ways to slow the growth of grass to reduce maintenance on golf courses, as well as lawns and parks. But conventional breeding by cross-pollinating different varieties is far more time consuming and less exacting than engineering specific genes.
Golf courses are sprayed with chemicals to slow grass growth, but they still must be mowed frequently.
Tim Norris, the golf course superintendent at the Army-Navy Country Club in Fairfax, Va., likes the idea of slow-growing grass.
"We're mowing every other day to try to keep conditions as good as we can," Norris said. "If we could have something that would cut down on the amount of mowing we do, it would be a great help. We could use our labor somewhere else."
The plants the Salk Institute scientists used in their study are more similar to trees, so there may be difficulties in getting the technology to work with grass, said Andy Hamblin, a turf geneticist at the University of Illinois. But it's only a matter of time before scientists develop grass that only needs to be mowed once or twice a year, he said.
Conventional varieties of grass take an average of 13 years to develop, and the latest breeds have reduced the number of mowings by only one or two times a year, he said.
Gene-engineered grass also raises environmental questions. Dwarf plants could cross-pollinate with standard plants and stunt the growth of their offspring, Hamblin said. The federal government would have to approve any new varieties of grass and could limit their use to avoid such problems. Hamblin said the approval process for a biotech grass could take several years.
As for its safety, the researchers said there should be no danger to children or animals from eating the grass, since it is essentially the same as conventional grass.
Lawnmower manufacturers are not worried, at least for the time being. Even with a government seal of approval for biotech grass and its widespread availability on the market, homeowners are unlikely to go through the hassle of digging up their old turf and planting an entirely new yard.
And many homeowners cut their grass regularly because they like the way it looks, said Don St. Dennis, a spokesman for The Toro Co., which makes Toro and Lawn Boy mowers.
"It's not just the fact that it's long that makes it look like it needs to be mowed, but it's because individual blades of grass grow at different rates. Part of the reason people mow it is so that it has an even, uniform look to it," said St. Dennis.
The steroid that the Salk researchers manipulated primarily regulates the growth of a plant's stems. It's release is ordinarily triggered by changes in light
Chory said scientists expect eventually to be able to pinpoint and alter other genes that that control the growth of leaves and flowers, enabling them to regulate the appearance of an entire plant. --
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Last Updated on 9/26/99
By Karen Lutz