All botanical discoveries from the palace were stored at the Bar-Ilan University in Tel Aviv for 40 years before Sallon and her team tried to germinate three date palm seeds in 2005.
Only one, Methuselah, yielded a tree.
At the beginning its leaves were plagued with white spots, which the researchers chalked up to insufficient nutrients.
These days it looks like a healthy modern date palm. But unlike its descendants, Methuselah grows better in fresh water than brackish water.
That's because the older version of the tree was usually found near freshwater oases, farther from the Dead Sea, Sallon said.
A study on Methuselah appears tomorrow in the journal Science.
Paul Gepts, a biologist at the University of California, Davis, was not involved in the study.
Methuselah "opens a small window into life [in Jerusalem] two thousand years ago," he said. (See photos of ancient Jerusalem sites.)
But he's not sure how valuable a single specimen will be for studies of date palms' genetic diversity.
"How much can we learn from one individual?" he asks. "Normally, palms are cross-pollinated. One would expect them to be very diverse."
Sallon agreed, adding that the plants are "a bit like people. If I wanted to say, What does this one say about a population, it doesn't say much. We're hoping just to germinate more date seeds."
But Methuselah holds potential beyond genetic studies, Sallon said.
Judean date palms once formed thick forests throughout the Jordan River Valley. Today, Israel imports its date palms.
If Methuselah is female—which should be known by 2012, when the plant would be ready to bear fruit—it might support species-restoration efforts.
Sallon also wants to know if the plant may have medicinal properties, as the ancients believed. But any real medicinal value will come from its dates.
No celebrations are planned if and when a first date appears, Sallon said.
"We will celebrate when there is peace," she said. "We will celebrate when all people in this region can plant these trees together, and share any medicinal benefits it brings."
SOURCES AND RELATED WEB SITES