2008-07-30 03:10:51 GMT 2008-07-30 11:10:51 (Beijing Time)
SINA.com This image shows pollen tubes extending from grains of
pollen in the rare vine Austrobaileya. University of Tennessee,
Knoxville, researcher Joe Williams found that the tubes' ability
to grow quickly played a major role in the evolution of the
large variety of flowering plants. What began with an off-the-
cuff curiosity eventually led Joe Williams to hang from the
limbs of a tree 80 feet above the soil of northeastern
Australia. The things Williams, a University of Tennessee,
Knoxville, researcher found there may help explain the amazing
diversity in the world's flowering plants, a question that has
puzzled scientists from the time of Charles Darwin to today.
Williams' findings, published online this week by the
Proceedings of the National Academy of Sciences, show that the
ability of flowering plants -- known as angiosperms -- to
quickly and efficiently move sperm from pollen to egg through a
part of the plant was the key to their evolutionar