March 25, 2000
Rose Is a Rose Is a ... Nut?

By JOYCE JENSEN
Flowers are a source of romantic inspiration, aesthetic meditation, perfumed
essences and food.

Considering the central role they play in human life, it is a shame that more
attention isn't given to the science of plants in general, says Peter
Bernhardt, a professor of biology at St. Louis University.



Peter Bernhart
Fluorescence micrograph of the germinating pollen of a canola oil flower.
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"I think we are severely depriving young American citizens of a very basic
education in plant life," he said. "They are a major part of how this world
works."

Mr. Bernhardt's specialty is floral biology. Right now he is looking at
similarities between flowers and their extinct ancestors, whose fossils are
found in deposits of clay, sedimentary stone and amber from the Cretaceous
Period.

"I want to compare the structure of fossils of flowers that are between, say,
100 to 120 million years old, against the flowers of live plants that still
retain aspects of the anatomy and shapes of fossil forms," he said. "These
include plants that give us water lilies, the black pepper we grind onto our
food, a group of vines that are often called cup and saucer magnolias, or
Schisandra, and the star anis bushes -- Illicium -- found from Florida to
Louisiana."

By examining the anatomy and chemistry of these living species and their
pollinators, Mr. Bernhardt is hoping to tease out clues to the basic
mechanics of plant reproduction. Eventually floral biologists may be able to
use these living survivors, or what are known as relic flowers, to answer
more sophisticated questions about flowering and fertility in more recently
evolved groups like pumpkins and roses.

"The whole point of comparing a relic like a pepper vine against something
more recent like a squash or a rose is that it gives you an idea of how
flower organs and chemicals have changed over time," said Mr. Bernhardt, who
is also a research associate of the Missouri Botanical Garden in St. Louis
and the Royal Botanic Garden in Sydney, Australia.

Although the natural breeding systems of most citrus fruit, the commercial
tomato, many cereal grains and a few other plants have been altered, in a
majority of cases the ancestral breeding system has remained intact, so that
crop, fiber and timber plants still require cross-pollination.

That is one reason farmers still don't have dependable yields of fruit and
seed, said Mr. Bernhardt.


University of Florida via The Associated Press
A 140-million-year-old fossil, the world's oldest flowering plant.
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"For example, cold spring temperatures mean sluggish or inactive honey bees
right at the time when peach and apple blossoms most need their attention,"
he said.

He said that advances in technology were raising tricky issues.

Scientists are patenting new life forms, for example: "When bees travel
between a new genetically altered crop and an old breed of crop exchanging
genes between two different crops owned by two different people, who owns the
genes in the next generation of seeds?"

Interest in relic flowers arose near the end of the 19th century, when a few
flower fossils had been found, he said. Spectacular fossil finds in New
Jersey as well as in Australia, Lebanon and Eastern Europe have
revolutionized the field in the last three decades, as have new techniques
that reconstruct evolutionary histories using molecular evidence inside the
cells of living plants.


Mr. Bernhardt is planning a trip to northern Australia to study members of
the macadamia nut family.

"Why the macadamia nut family?" Mr. Bernhardt said. "The flowers in this
family, especially those that are found in the rain forest, show flowers that
have structures that appear to be intermediate in structure between those
primitive relic flowers and more modern roses, squashes and orchids."

"People will ask the question, What's so great about the macadamia nut
family? Well they are celebrities," he said.

"You see them on television quite frequently. The flowers of these plants
look so peculiar to most Americans that they are regularly used as alien
flowers on most of the 'Star Trek' television shows."