on Flower Power
Using Arabidopsis, biologists have discovered the "flower
genes" in plants. When the genes are switched on, the plant blooms.
Credit: Stephen Webster
Plants begin to flower when one of two internal
genetic switches is turned on, NSF-funded biologists have discovered.
With this knowledge, the scientists are using genetic engineering to manipulate
the blooming process.
Working independently, groups of scientists from the Salk Institute for Biological
Studies and the University of California at San Diego demonstrated that when
one of two genetic switches is flipped, the plant will stop adding to its stem
or root system and concentrate all of its efforts, instead, on blossoms.
"We have virtually complete control over the onset of flowering," Martin Yanofsky,
senior scientist of the UC San Diego team, told The Los Angeles Times.
Scientists used the two genetic switches, known as the Leafy and the Apetala1,
on such diverse plants as the mustard family's Arabidopsis and tobacco
and aspen trees.
In aspens the result was particularly dramatic. Aspens normally take 8 to 20
years and 30 feet of growth to flower. But the transformed seeds wasted little
time on normal growth patterns, flowering when they were only six months old
and two inches tall.
"We've transformed the aspens from trees into weeds," Detlef Weigel, leader of
the Salk team, told The New York Times.
Weigel expects the discovery to encourage commercial tree breeders who are currently
constrained by the long life cycle of trees.
In addition, the discovery could cut as much as 70 percent of the time needed
to breed new seed varieties and could lead to genetically engineered crops that
need less time to reach maturity.