“The real question is not why regeneration was
lost but why it was ‘won.’” —LuiS CovarruBiaS
Sawfishes don’t
live up to name
By Susan Milius
Sawfishes use their spiked snouts as a
combination sword, antenna and serving spoon — but not much at all as a saw,
scientists have found.
Figuring out how the fishes use their
whopper snouts has been tricky, says
Stephen Kajiura of Florida Atlantic
University in Boca Raton. Most of these
rare and endangered relatives of sharks
and rays live in murky waters or have
been trained to captive-feeding regimens in big aquarium displays.
But Barbara Wueringer of the Univer-
sity of Western Australia in Crawley got
a rare chance for a more natural look at
a freshwater sawfish, Pristis microdon, in
tanks in Australia just after the fish were
collected from the wild. “Now we actu-
ally have some empirical evidence” for
what the saw does, Kajiura says.
Sawfishes use their snouts to slash at
prey and to sense moving water and
the weak electric fields that betray the
locations of prey.
in the water and found that setting off an
electric signal with no prey fish attached
still prompted the sawfish to try to bite.
This experiment clarifies that just
sensing an electric field is enough to trigger a sawfish attack, says neuroscientist
Carl D. Hopkins of Cornell University,
who has studied the electric world of
fishes. “It really is an amazing story.”
Plant grown from an ancient fruit
Squirrel’s stash spent 30 millennia in Siberia’s permafrost
ago, came from a recently excavated
cache of provisions that a squirrel stuffed
into a burrow 38 meters underground.
Tissue scraped from the fruit and bathed
in nutrients grew into fertile plants with
healthy seeds that sprouted in soil.
“It is remarkable that under deep
freeze, fruit tissues … can
remain viable for such a
long time,” says UCLA
biologist Jane Shen-Miller.
“This is like regenerating
a dinosaur from tissues of
A flower that last bloomed while mammoths walked the Earth has been reborn,
regenerated from a piece of fruit frozen
in Siberian permafrost.
It’s the oldest flowering plant ever
grown from preserved tissue, scientists report in the
March 6 Proceedings of the
National Academy of Sciences. David Gilichinsky,
who led the team at the
Russian Academy of Sciences’ research institute in
Pushchino, died just before
the paper was released.
The fruit, radiocarbon-dated to about 31,800 years
Scientists grew this flowering plant from bits of a
fruit preserved in Siberian
permafrost for more than
31,000 years.
an ancient egg.”
At first the reconstituted plants,
identified as the extant species Silene
stenophylla, looked exactly like their
modern relatives. But when flowers
appeared, the white petals of the reborn
plants were narrower and less separated
than those of the modern species.
The hardiness of an ancient plant’s
frozen tissue is good news for Norway’s
Svalbard Global Seed Vault and other
projects freezing seeds to safeguard
against the extinction of modern plants.
“No one knows how long [frozen seeds]
are viable for, but freezing is basically the
format for all seed conservation attempts
nowadays,” says Sarah Sallon, director
of the Louis L. Borick Natural Medicine
Research Center at the Hadassah Medical Organization in Jerusalem. Several
years ago she helped grow a date palm
from a 2,000-year-old seed unearthed in
Israel (SN: 7/5/08, p. 13).
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April 7, 2012 | SCIENCE NEWS | 15
